Man's inner self is the commanding power inside him and knows both depravity and how to avoid it. In other words, it is the inner self which inspires evil and wicked deeds. God relates these two features of the inner self in the Qur'an as follows:
And the inner self and what proportioned it and filled it with both its debauchery and its sense of duty, he who purifies it has succeeded. (Surat ash-Shams: 7-9)
The inner self is mentioned in the verses as the source of all depravities and wrong acts of people. Having such a feature, the inner self is among the most avowed enemies of mankind. The inner self is arrogant and selfish; it always wants to satisfy its own desires and vanity. It cares only about its own needs, interests and seeks only pleasure. It resorts to every means to tempt mankind since it is not always possible to fulfil its wishes through legitimate ways. The words of the Prophet Joseph explains this fact in the Qur'an as follows:
I do not say I free my self was from blame. The inner self indeed commands evil acts - except for those whom my Lord has mercy on. My Lord, He is Forgiving, Merciful.' (Surah Yusuf: 53)
That one's inner self vigorously inspires evil and wicked deeds is a very important secret revealed to believers having fear of God. This way, they know that the devices of the inner self will never cease, not even for a single moment. Through temptations, it continuously tries to lead man astray from God's way. In accordance with this secret, the inner self will never remain silent; it will justify its deeds under all circumstances, will love itself more than all others, will grow arrogant, will desire to possess everything good and will desire to lead a life of pleasure. In brief, it will resort to any means to make a person display the type of an attitude contrary to the morality which would please God.
Indeed, the behaviour and manners of disbelievers, which do not comply with the morals of the Qur'an, are shaped completely by their inner-selves. Having no fear of God, disbelievers cannot demonstrate the will to obey their conscience but rather follow their inner-selves. Quarrels, conflicts of interests and unhappiness raging in societies in which the morality of the religion is cast aside, have their roots in individuals' plunging into their inner-selves and their own interests and consequently, losing all their humane attributes such as true love, respect and sacrifice.
That is why this secret revealed by God is of great importance. As long as one keeps this secret in mind, he can take precautions against his inner self and assume the correct way of conduct. The inner self can be disciplined by doing just the opposite of what it commands. For example, when the inner self commands laziness, one must work harder. When the inner self commands selfishness, one must become more self-sacrificing. When the inner self commands stinginess, one must become more generous.
Apart from the wicked side of the soul, from Surat ash-Shams, we know that God also inspired in the soul a conscience which makes a person restrain his soul from fulfilling lower desires. That is to say, next to an inspiration instigating the soul to evil, the soul is also open to instigation of righteousness. Every man is aware of these whispering voices and recognises the evil and the righteous one. Yet, only those who fear God follow the voice of their conscience.