The victorious trait determines the soul's inclination.
In a hadith from Imam 'Alī ibn Abī Tālib, he is related as saying: "Surely God has characterized the angels by intellect without sexual desire and anger, and the animals with anger and desire without reason.
The soul becomes accustomed to repeated behavior, which then determines actions.
Noble faculties manifest moral and wise behavior, while evil faculties manifest immorality. Moral virtues bring eternal happiness and well-bring (falaḥ), while moral corruption leads to everlasting wretchedness.
If reason controls the other faculties, it moderates excesses and ensures useful performance.
Allah says in surat Ash-Shams: "And by nafs (soul), and Him Who perfected him in proportion; Then He inspired him corruption and its righteousness; Indeed he succeeds who chooses to purify his own self; and indeed he fails who corrupts his own self." The soul is in a continuous jihad (struggle) between these four powers for domination.
If man travels the path of purification, God will aid and guide him.