O Believers! Repent to Allâh truly and sincerely [Al-Tahrîm (66): 8]
In explanation of this verse, Al-Tabarî reports the following narrations in his Tafsîr:
He reports that ‘Umar b. Al-Khattâb – Allâh be pleased with him – was asked about true repentance. He replied, “It is that a man repents from an evil deed, and never does it again.” He also reports that ‘Umar said, “It is that you repent from the sin and never do it again, or never intend to do it again.”
Similarly, he reports from ‘Abdullâh (Ibn ‘Abbâs) – Allâh be pleased with him – that he said, “A person repents, and then never goes back to the sin.”, and “It means that a person never returns to the sin from which he repented.”
Mujâhid is quoted as saying, “They seek Allâh’s forgiveness and then never go back to sin.”
Qatâdah is quoted as saying, “It is the true and sincere repentance.”
Al-Tabarî, Tafsîr Al-Tabarî, in the commentary on Sûrah Al-Tahrîm.