The Religion Of Islam vol.1
The Koran and the Doctrine
of Personal Holiness
Islam has taken due cognisance of the frailties of human nature, and this constitutes its chief excellence as a system of religion. Thus, the laws of Islam exhibit elasticity, which is a proof of their beneficence and usefulness. Though Islam, no doubt, points to a lofty idealism, it is, at the same time, thoroughly practical. The merit of Islam, as a religion, consists in a happy harmonious blending of the ideal and the practical. It favour no form of asceticism, and never asks any man, to do what he has not the power to do. There is, however, one thing, on which it lays the greatest emphasis. It is personal holiness and purity of heart. It is the grand purpose, for which the Prophet was sent down, as it appears from the prayer of Abraham: “Our Lord, raise up among them an apostle who may rehearse Thy signs unto them, and teach them the Book and Wisdom, and purify them.”  The reader will observe that the verse gradually ascends to a climax. Purification of men being put last as the most important part of the functions of the Prophet of Islam. “He who is purified, hath obtained felicity,” says the Koran elsewhere.”  Again, after mentioning the blessings of heavenly life, the Holy Book adds: “And this shall be the reward of him who shall be pure.”  That a very important place is given to purity of mind and personal holiness, will be seen from another verse, where sinners are threatened with the punishment, that God shall neither speak unto them nor shall He purify them.” “Moreover, they who conceal any part of the scripture which God hath sent down unto them …God shall not speak unto them, on the day of resurrection, neither shall He purify them, and they shall suffer a grievous punishment.”  It is clear, then that communion with the Deity and personal holiness are the keynote of Islam.
But even here, man is not held responsible for the evil thoughts that in spite of himself, pass through his mind, like flashes of lightning. To render man responsible for such passing fancies, over which he has little control, would be sheer injustice. Commission of a wrong act, without previous intention and deliberation does not make one guilty, far less a passing thought that rises like a bubble only to die and disappear the next moment. Adam ate of the forbidden fruit and thereby committed a mistake as all men are liable to commit mistakes; but he was never guilty of committing sin, and the Holly Koran clears him of the false accusation, just as it has cleared other prophets, like Moses and Jesus of similar charges. For it says: “We heretofore gave a command to Adam, and he forgot it and We found no intention in him (to disobey our command)”  This is, indeed, an important principle, and it has important bearings on the doctrine of sin, as presented by the Holy Koran, for elsewhere we read: “God will not punish you for an inconsiderate word in you oaths; but He will punish you for that which your hearts have assented unto.”  This verse clearly lays down, that a wrong act, or an evil thought, is a sin, if it is deliberate. Shorn of intention and deliberation, a wrong act or an impure thought is a mere accident which, however deplorable, cannot prove the doer a guilty sinner in the sight of God.
But, if the element of intention is present, even the faintest thought is enough, to render a man guilty before his Maker, not to speak of a deed which is manifestly wrong. God forbids both kinds of sin –open and secret– equally in the same verse: “Draw not near unto sin neither open nor secret,”  “Leave both– the outside of iniquity and the inside thereof.”  Again: “Say, verily, my Lord hath forbidden sins, whether open or secret and iniquity and unjust violence.” 
These verses sufficiently establish the doctrine of personal holiness in Islam; but to crush the objection of the critics absolutely, we give one more verse which shows, that not only the eyes and the ears, but also the heart, will be required to give evidence on the Day Judgment, if any sin has been committed through them. And the verse is this: “And follow not that, whereof thou hast no knowledge; for the hearing and the sight and the heart – each of these shall be examined.” 
Personal holiness, it must be remembered depends largely on a thorough belief in the Omniscience and Omnipresence of God. And nothing is more striking to the reader of the Holy Koran, than the force, with which it impresses upon us these two attributes of the Deity. The belief, that the Supreme Being sees our actions and knows even the innermost secrets of our hearts, is a most powerful check upon the tendency to commit sin. So long as a man realizes, that he works and moves under the great Task master’s eyes he keeps himself from vice: but whenever this consciousness in him grows dim, and he thinks he is not watched by God, he exposes himself to constant danger.
() Koran, XX : 114. It is interesting to note, that the word ….(‘Azma) in the verse quoted, has been taken, both by Rodwell and Sale to mean ‘firmness of purpose’ and not ‘intention.’ Hence, Mr. Wherry says in his commentary: “This verse is fatal to the Moslem theory of the sinlessness of prophets.”