O Believers! Repent to Allāh truly and sincerely [Al-Taḥrīm (66): 8]
In explanation of this verse, Al-Ṭabarī reports the following narrations in his Tafsīr:
He reports that ʿUmar b. Al-Khattāb – Allāh 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 ʿUmar 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 ʿAbdullāh (Ibn ‘Abbās) – Allāh 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.”
Qatādah is quoted as saying, “It is the true and sincere repentance.”
Al-Ṭabarī, Tafsīr Al-Ṭabarī, in the commentary on Sūrah Al-Taḥrīm.