The Holy Qur’an explicitly explains the concept of good and evil, by declaring that the consciousness of good and evil is imbedded in the human nature. The verses discussing this topic are as follows:  

By the Soul, and the proportion and order given to it; and its enlightenment as to its wrong and its right. (91:7-8)  
 
We showed him the right and wrong path. It is now up to him to be grateful or ungrateful. (76:3)  

Have We not made For him a pair of eyes? And a tongue, And a pair of lips? And shown him the two paths (of good and evil)? (90: 8-10)  

So set thou thy face steadily and truly to the Faith; (Establish) Allah’s handiwork according to the pattern on which He has made mankind: no change (let there be) in the work (wrought) by Allah: that is the standard religion; but most among mankind understand not. (30:30)  

In fact, he himself is a witness upon his own self however much he may put up excuses. (75:14-15)  

    These passages of Qur’an elaborate five points:  

1. Firstly, Almighty has sent man in this world with a clear consciousness of virtue and vice.  
2. Secondly, God has created man with a distinct nature.  
3.Thirdly, this consciousness of good and bad is a part of human nature.  
4. Fourthly, it is not lawful for man to change this nature created by God.  
5.Lastly, Man is fully aware of the facts of his nature.  

    A deep analysis of the verses reveals that, it is being said that God has granted the consciousness for judging good and bad, not that he has created man as good or bad. Now it is the free will of man which helps him decide which path to follow.  
    It becomes clear from the Qur’an that the awareness about good and evil is a part of human nature. It neither accepts the notion that these are relative values nor it considers intention, pleasure, happiness and profitability its basis.  
    According to the Qur’an it is something which is inborn. Man is fully aware of the realities that are a part of his innerself although he may negate them.  
    Is this concept of Qur’an undeniable? It is noteworthy that when man commits a sin, he does not do so because his intellect demands so and some reasoning diverts his course or because it was some kind of responsibility, the denial of which would have caused him embarrassment. Whenever man commits evil it is either because of his blind lust or he sometimes starts considering vice as virtue because of some fallacious logic. Man existing at any time or place has always had a clear understanding of good and evil. Never in this world man has accepted any evil for himself. Every person, whether he is a source of advantage or disadvantage to others, never likes to be harmed by anyone. No thief ever likes to keep a servant who is a thief himself or a selfish person would never like to be treated selfishly at the time of his own need or an unjust person never likes to be treated unjustly by the judge.  
    What is the reason for this behaviour of man which impels him to accept truth, honesty, justice, sacrifice and compassion for himself from others. Whether he adopts such behaviour with others or not he would always like to be treated in the best manner possible. This rule has never been negated in this world. Is it because of the fact that people throughout the world in every age get together and reach a consensus over this issue and then nobody ever goes against it? If it is not like this then what is the reason for this common behaviour of mankind.  
    Some intelligent people have tried to answer this question. They say that the environment of man conditions him to some set ideas and beliefs, and then man becomes bound to act according to them. Because over the past thousands of years society has taught mankind a lot about morals, that is why we find perfect harmony or, more precisely, stagnation as far as morals are concerned.  Otherwise it is not true to say that some values are inborn.  
    But there exists a confusion in this point of view. The question arises, if man does not possess some inborn values and whatever morality he has is the result of society’s teachings then how did the society acquired those values in the first place on the basis of which it conditions mankind? Society itself consists of a group of humans. If man does not have a nature, conscience and intuition then how does it become possible for the society, which consists of human beings, to condition people to certain rules and ideas.  
    Holy Qur’an describes the reason for this consensus on morals and values. It asserts that all human beings are created on the same nature. It is in the nature of every human to accept good values and morals for himself and reject the opposite. This is the reality which dwells in the heart of man. Every person is aware of it and everyone faces it. This is one of those realities which if denied makes the universe meaningless. No bases are left for man to ponder and he cannot exchange views with anyone, neither can he co-exist with anybody.  
 
Human Conscience  
    Almighty has not just created man with the awareness of good and evil, he has gifted man with a hidden conscience, which pushes him towards good and stops him from committing evil. Qur’an calls it the ‘reproaching soul’.  

I present as evidence the Day of Judgement itself. And [they think that the Day of Judgement is a far-fetched reality]. By no means! I present as evidence this reproaching soul [within you]. Does man think that We will not be able to bring together his bones? Why not? We can put together his very finger tips. [No this is  not so]; in fact [the truth is that] man wants to be mischievous before his [conscience]. He asks ‘When will the Day of Judgement be?’ (75:2)  

    This reproaching soul is a great reality and nobody can deny its existence. This is the voice from within which echoes in favour of good, and thunders to stop man from committing evil. This human conscience is another reason for the fact that the awareness of good and evil is a part of human nature, and man has acquired this awareness from the same source from where this conscience has been sent forth.  
    It is not true that man has been adorned with a conscience but is devoid of any human nature. In that case what standard would the conscience have set to censure man. Would it censure man on the basis of material profit and loss? Then it would have been fruitless because man is already very sensitive about his material gains and losses. Does the conscience reproach man when he violates the norms of the society? This is also not true because observing the norms of society is a problem of society, not of man. If we are ready to accept the truth then the simple fact remains that man is born with a conscience accompanied with the awareness of good and evil.  
 
Collective Conscience of the World  
    Even if the leaders of a nation try to make people understand, through sermons, that certain actions fall under the category of good and certain other under evil, or good is bad and bad is good, it will be clear in any case that good and evil independently exist in reality and there is no need to prove their normative existence. Man is fully aware of it, infact man is aware of this reality to such an extent, that humanity has never cared about anything contrary to it. So the collective conscience of the world is witness to the concept of Qur’an, that this awareness of good and evil is rooted in the nature of man. Only a blind and insane person can deny it.  
    Whether we take a look at the savage tribes of the world or civilised nations, whether an ancient society is studied or the modern civilisation is under review, we do not find any community in which courts are set up for denial of justice, where laws are formulated to carry out punishment on innocents, where promises and pacts are made to be violated.  
    All the societies and nations of the world alongwith their systems of governance, their laws and their knowledge point towards the simple fact that man has always valued truth, honesty, justice and loyalty. Whether it is the family unit or the entire social fabric, the foundations are always laid on these principles.  
    The criticism on this notion can be in the form of a question that why can’t man think contrary to this. Because in history there are examples of Arab society which had a tradition of female infanticide, Spartans, who had the tradition of killing week children and Hindus, who forced the widow to die alongwith her dead husband in the process of cremation (sati). But a deep study of these nations reveals that all these traditions existed in these societies because of some wrong beliefs and due to tyranny of man on his fellow humans. Had these traditions been good, these societies would not have adopted them as external factors. Taking these examples one by one, we see that Arabs buried their daughters because of two reasons. Firstly because of a high degree of intertribal conflicts, vandalism was the order of the day. During its course women were made prisoners of war and ultimately sold as salve girls. This was a source of great embarrassment for a tribe. Secondly some Arabs had started considering it beyond there dignity to accept a man as their son-in-law. So these two apprehensions became so strong that Arabs started hating female child.  
    In second example, we see that Spartans were war-like people. Their obsession with war paved way for the notion that all the people of the society should be healthy and strong, because these are the qualities which lead to victory. So their indecent obsession made them kill all their weak and disabled children.  
    And in the third example, the Hindu tradition of Sati was actually the result of a social cruelty on women. They had developed an erroneous idea about women, which led them to believe that a woman is created only to serve man. If once she is associated to a man, then it is the inevitable demand of love and loyalty that she should not marry again after his death. In this situation the highest degree of loyalty was considered to be the tradition of Sati. Initially it was just a concept, but afterwards when the society started looking down upon widows, Sati seemed to be the only way for a widow to escape the wrath of the society.  
    In the above mentioned examples, had all the external factors not been present, history would have been devoid of such heinous traditions. That is why as soon as all these external factors ceased to exist, these societies also came back on the true human nature.  
 
Creator of Evil  
    It is a known fact that man is responsible for his deeds, whether good or bed. But the main question is that who is the creator of evil? What is its source? Whether it is the Almighty, who is the creator and the source of evil or has he created the basic element of evil in man which always gives birth to evil? Or is the reality different from that?  
    It is explicitly mentioned in the Qur’an that God is not the creator of evil, neither a direct source nor an indirect one. Infact it is beyond His grace to be the creator of evil. Qur’an has introduced Almighty as the only God to whom all the good attributes can be associated, and it also directs people to uphold good. It is said in surah ‘Araf  

The most beautiful names belong to Allah, so call on Him by them. (7:180)  

    And in Surah Al-Imran  

Let there arise out of you a band of people inviting to all that is good, enjoining what is right, and forbidding what is wrong: they are the ones to attain felicity. (3:104)  

    In these verses Qur’an has revealed that all the attributes belong to Allah and He is the source of all good. So no evil can be attributed to him. He is above and beyond to create any evil, whether directly or indirectly, in human beings. All His creations reflect good and He directs human beings to do good. It cannot be imagined that God is the creator of evil. This is far beyond His grace.  
    But even after admitting this, the question remains that if God is not the creator of evil then who created evil? Qur’an has answered this question.  
 
The Existence of Evil  
    To have an understanding of reasons for the existence of evil in this world, it is necessary to study the Divine scheme for human beings. According to this scheme God has granted man some capabilities and sent him in this world for a special purpose. Qur’an refers to these capabilities in the following words:  

Said thy Lord to the Angels: I will create ‘A vicegerent on earth.’ They said: ‘Wilt Thou place therein one who will make mischief therein and shed blood? -- Whilst we do celebrate Thy praises and glorify Thy holy (name)?’ He said: ‘I know what ye known not.’ (2:30)  

    This means that God has given the freedom of will to man, and along with this freedom He has also granted a whole world of emotions and desires. This fact is explained in the Qur’an in the following words:  

Fair in the eyes of  men is the love of things they covet: Women and sons; heaped-up hoards of gold and silver; horses branded; and (wealth of) cattle and well-tilled land. Such are the possessions of this world’s life. (3:14)  

    In surah Kuhaf this is also explained as follows:  

That which is on earth We have made but as a glittering show for the earth, in order that We may test them -- as to which of them are best in conduct. (18:7)  

    The special purpose for which man is sent to this world is described in these words in the Qur’an:  

Blessed be He in whose hands is dominion; and He over all things hath power; He Who created death and life, that He may try which of you is best in deed: and he is the Exalted in Might, Oft-Forgiving. (67:1-2)  

    It is made clear that through the circle of life and death, man is tested for his good and bad deeds. Later, it is also informed that this world and its belongings are a temporary and short phase. Almighty has said:  

Short is the enjoyment of this world. (4:77)  

    The fact, that God has granted free will to man and he is tested in this world through his deeds and ultimately he will be responsible for his acts, is repeatedly mentioned in the Qur’an. Two of these passages are as under:  

We showed him the right and wrong path. It is now up to him to be grateful or ungrateful. [We showed him the right and wrong path; so therefore] We have prepared for the ungrateful chains and yokes and a Blazing Fire. But [those who are grateful], the loyal, they indeed will drink cups of wine flavoured with camphor. (76:3-5)  

Say, ‘The Truth is from you Lord: Let him who will believe, and let him who will, reject (it): For the wrong-doers We have prepared a fire whose (smoke and flames) like the walls and roof of a tent, will hem them in. (18:29)  

    All these verses reveal the Divine scheme for man, on the basis of which he is put to this test of good and evil. For this test man is granted the freedom of will and action. Now it depends on each person, whether he follows the voice of his intellect or not. It is totally upto man to obey or disobey the Almighty. God has made it possible for man to completely negate his human nature, if he wants to, and leave  aside all his responsibilities. Anyhow, whatever path man decides to follow, his reward would be according to that.  
    Almighty has granted man with freedom of will and action and virtuous nature with a lot of desires. But no one can fulfil all his desires in this world, as this world is limited. So if man decides to follow his nature then it is necessary for him to limit his desires and emotions. To the contrary, if man lets his desires go wild, then he has to crush his own nature and intellect. So whenever man used his freedom of action in favour of his nature and intellect, it gave birth to good. On the other hand whenever man did the opposite, he became a source of evil. It is clear from this discussion that evil is only a result of the wrong use of man’s freedom of action and his will.  

Universality of the Concept of Good and Evil  
    The last question that remains to be dealt with is that if man has inherent awareness of good and evil in his nature, then why there is a difference of opinion about it between various nations and religions.  
    The notion of difference of opinion about good and evil between different nations is incorrect. The reality is that there is a difference of religious concepts, civilisation, social norms and traditions, external and internal environment between these nations. It is because of this difference that certain concepts have prevailed in different areas of the world. But neither the human intellect nor the collective conscience of the world ever accepted these concepts as good. That is why these wrong traditions ultimately met a fatal blow, as the collective conscience of the world condemned them in every degree. Does this really prove that there ever was a difference between the concepts of good and evil among various nations of the world? Has the world ever disagreed on the concepts of justice, truth, honesty, loyalty, trust and love. The truth is, whether it is east or west the world has always accepted these concepts as good. However, there has always been some philosophers who disagreed on these concepts. But all their debates and disagreements never changed the collective thinking of the world. Almighty has bestowed mankind with a collective conscience and granted man the awareness to decide between right and wrong, so whenever a society reached the limit of moral decadence, it was wiped out from the face of the earth, so that man should not set an example for himself on the basis of that corrupt society and create confusion about the inherent concepts of good and evil. Had this awareness of good and evil not been a part of the human nature, mankind would have been divided on this issue.  

Summary  
    Man has never faced any confusion about the concept of good and evil because Almighty has granted man the consciousness of good and evil in his nature. This reality is known by all alike. By nature man likes virtue and detests vice. Evil does not have a continuous existence in this world. It is only an outcome of the wrong use of freedom of action by man.