Imām Ibn al-Qayyim [d. 751 AH] said:
Acts of disobedience have ugly, blameworthy, and harmful side effects that extend to one’s heart, body, the worldly life and the hereafter; [the details] of which no one is fully aware of except for Allāh.
From them is that acts of disobedience weaken the heart and the body. As for its weakening of the heart, it is an apparent matter. For it continues to weaken it until its very life ceases.
As for its weakening of the body, a believer’s true strength comes from his heart. If his heart increases in strength, so does his body.
Imām Ibn al-Qayyim
As for the...