Nahj al-Balāgha

Hadith 2010
repentance
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.
Source: al-Sharīf al-Raḍī