What should a person do if their heart goes astray?

Whoever's heart has deviated should turn to Allah in supplication, remain steadfast in faith, read books on encouragement and warning, strive to do good, and avoid evil. He should also frequently read the stories of the prophets, companions, and righteous people, and stay away from sins and neglecting to act upon knowledge, as this can lead to the punishment of misguidance and deviation. Ibn al-Qayyim and Ibn Taymiyyah mentioned that Allah does not misguide except after clear exposition and confirmation, and that abandoning acting upon knowledge and inclining away from the truth after knowing it leads to the removal of guidance and the deviation of hearts.