'Lest a soul should say, "Oh, my regret over what I neglected in the side of Allah"'—that is, regarding the command of Allah—'and indeed, I was among the mockers'—that is, I used to mock the Prophet and the believers in the worldly life.

Muhammad said: 'Lest a soul should say' means: fearing that a soul might say [this] when it arrives at a state of remorse, and the preferred recitation is 'Ya hasrata' (Oh, my regret).

Tafsir of Surah Az-Zumar from verse 57 to verse 63.