The Essence of Islam – Volume II — Page 184
184. Essence of Islam II should be such that he cannot commit any vice, he cannot deserve any merit either. For instance, our systems do not secrete, like scorpions and snakes, a kind of poison through which we could hurt anyone like scorpions and snakes. We cannot, therefore, deserve any merit in the estimation of Allāh by refraining from causing such harm. . This shows that opposing emotions which pull a person towards vice are the cause of merit for him, for when out of fear of God he discards such emotions, then he becomes worthy of praise in the estimation of God and wins His pleasure. He who arrives at the extreme point of virtue and is rid of all opposing motions as if his Satan had become a Muslim, would still deserve merit for he has traversed the stages of trial with great courage. A righteous person who in his youth has accomplished many great works receives merit for them even in his old age. [Ā'ina-e-Kamālāt-e-Islām, Rūḥānī Khazā'in, vol. 5, pp. 80-85, footnote]. Some foolish people object to the existence of Satan, as if God Himself desired to lead people astray. This is not so. Every intelligent person can understand that everyone has two faculties, one is called the touch of Satan and the other is called the touch of angels. That is to say, human nature displays that sometimes through unknown means a good idea is generated in a person's mind and his heart inclines towards good works, and then sometimes an evil idea rises in his mind and he is inclined towards vice and wickedness and wrong and evil. The power that is the source of evil thoughts, according to the Qur'ānic teaching, is Satan, and the power that is the source of good ideas is an angel. [Chashma-e-Ma'rifat, Rūḥānī Khazā'in, vol. 23, p. 435]