Alī ibn Abī Tālib—may Allah be pleased with him—likewise regretted certain things he had done, including fighting and other matters. He would say:

“I showed weakness once, for which I offer no excuse;
Henceforth I shall act wisely and remain resolute,
And gather together my scattered, dispersed judgment.”

During the nights of Siffīn, he would say:

“What an admirable stand Abd Allāh ibn Umar and Sa'd ibn Mālik took! If it was righteous, its reward is indeed immense; and if it was sinful, its gravity is indeed slight.”

He would also say:

“O Hasan! O Hasan! Your father never imagined that matters would come to this. Your father wishes he had died twenty years before this.”

When he returned from Siffīn, the tenor of his words changed. He would say:

“Do not resent the rule (1) of Mu'āwiya. If you were to lose him, you would see heads flying from their shoulders.”

This has been reported from Alī—may Allah be pleased with him—through two or three routes of transmission. Reports are so numerous as to establish his disapproval (2) of the state of affairs toward the end, when he witnessed the people’s dissension and division and the profusion of evil. Consequently, had he known at the outset what he came to know afterward, he would not have done what he did.

In sum, we are not required to know that every single person repented. We do know, however, that repentance is prescribed for every servant—for the prophets and those of lesser rank—and that Allah, Glorified be He, raises His servant through repentance. When He tries him with something from which he then repents, what matters is the perfection of the end, not the deficiency of the beginning. For the Exalted loves those who constantly repent and loves those who purify themselves, and through repentance He transforms evil deeds into good deeds.