What should one do who is affected by the second part of the Hadith: "Whoever introduces a bad practice will bear its sin and the sin of everyone who acts upon it until the Day of Resurrection," in many matters?

Whoever calls others to disobedience or misguidance bears his sin and the sin of those who follow him. He must offer sincere repentance that fulfills the conditions of repentance: remorse, cessation (of the sin), and a firm resolve not to return to it.

If he is able to remove the evil he caused, then he must remove it. If he is unable, then we hope his repentance is valid.

The majority of jurists of Usul have affirmed the validity of the repentance of one who called to misguidance, even if its effect remains, because repentance is an obligation, and he has fulfilled what he is capable of, and he is excused for what he is not capable of. We advise anyone who initiates a bad practice to repent sincerely to Allah, for Allah forgives all sins.