one of them says, “Allah will never accept my repentance.”
The first view is refuted by Allah’s Book, the Sunnah of His Prophet, and the consensus of the Muslims. Some scholars have, however, discussed the repentance of a murderer and of one who calls others to religious innovations. There is disagreement on this within Ahmad’s school, and within Mālik’s school as well, as mentioned by the author of al-Tamthīl wa-l-Bayān in al-Jāmiʿ and elsewhere. They have also discussed the repentance of a zindīq (heretic) and similar cases.
They may disagree over whether outwardly professed repentance averts punishment, either because its sincerity is not known or because it does not cancel a prescribed punishment that has already become due. Yet no jurist has said that if a zindīq or someone like him sincerely repents before Allah, Allah will not accept his repentance. As for the murderer and the person who leads others astray, the issue concerns the rights that others have against them. Repentance for violations of people’s rights is a separate matter, and this is not the place to discuss it or its details. The point here is simply that Allah accepts repentance from every sin, as the Quran and Sunnah indicate.
As for acts of sexual immorality in particular, I know of no one who has disputed that repentance from them is accepted. The one who commits illicit intercourse and the one with whom it is committed are alike in this: if they repent, Allah accepts their repentance. What Allah relates in the account of the people of Lot makes clear, in particular, that repentance from the act of the people of Lot is open to both participants. They used to commit this indecency with one another, yet He called upon them all to fear Allah and repent of it. Had the repentance of the receptive participant, or anyone else, been unacceptable, He would not have commanded them to do something that would not be accepted. The Most High says:
“The people of Lot rejected the messengers.”
“When their brother Lot said to them, ‘Will you not fear Allah?’”