“For a seed is not an apple tree or a date-palm: it has merely been created in such a way as to permit it to become one when it is properly nurtured; and even when nurtured, a date-stone can never become an apple tree. Therefore, just as a seed is affected by human choice, so that it is susceptible of acquiring some qualities and not others, so also anger and desire, which we cannot suppress and dominate entirely so as to destroy every trace of them, can be rendered, should we so wish, obedient and docile by means of self-discipline and struggle. And this we have been commanded to do, for it constitutes the means of our salvation and our coming to God.”
~ Imam Al-Ghazali
Al-Ghazālī On Disciplining The Soul – Kitāb Riyādat al-Nafs & on Breaking The Two Desires – Kitāb Kasr al-Shahwatayn, Books XXII and XXIII of The Revival of the Religious Sciences – Ihya-Ulūm al-Dīn, translated with an introduction and notes by T.J. Winter, page 25.