True meaning of istighfār in Islam
Nahj al-Balāgha|Volume 1|Book 3|Chapter 417
وَالسَّادِسُ: أَنْ تُذِيقَ الْجِسْمَ أَلَمَ الطَّاعَةِ كَمَا أَذَقْتَهُ حَلاَوَةَ الْمَعْصِيَةِ.
and the sixth is to make the body taste the pain of obedience as you (previously) made it taste the sweetness of disobedience.