COMMENTARY on 40:55
Mustafa Khattab:

Translation:
So be patient ˹O Prophet˺, ˹for˺ Allah’s promise is certainly true. Seek forgiveness for your shortcomings.9 And glorify the praises of your Lord morning and evening.
Commentary:
9   Like other prophets, Muḥammad (ﷺ) was infallible of sin. The verse here refers to misjudgments, such as the Prophet’s response to the blind man (80:1-10), Jonah’s departure from his city without Allah’s permission (21:87-88), and David’s suspicions of the two men who scaled the wall of his sanctuary (38:21-25). If the Prophet (ﷺ) himself is urged to seek forgiveness, then the believers are even more in need of praying for Allah’s forgiveness.

 

A. Yusuf Ali:

Translation:
Patiently, then, persevere: 4427 for the Promise of Allah is true: and ask forgiveness 4428 for your fault, and celebrate the Praises of your Lord in the evening and in the morning. 4429
Commentary:

4427  The Israelites corrupted or lost their Book: they disobeyed Allah's Law; and failed to proclaim and exemplify Allah's Message. That is why the new Revelation came to the Prophet. If, in the beginning, it was rejected and persecuted, there was no cause for discouragement; on the contrary, there was all the greater need for patience and perseverance.

4428  Every mortal according to his nature and degree of spiritual enlightenment falls short of the perfect standard of Allah (16:61), and should therefore ask Allah for forgiveness. What is merit in an ordinary man may be a human shortcoming in one nearest to Allah: see 38:24-25, and notes 4175-4176. Prophets have a further responsibility for their People or their Ummah, and they ask in a representative capacity.

4429  Cf. 3:41 . Evening and morning are the best times for contemplation and spiritual effort. But the phrase "evening and morning" may mean "at all times". (R).

 

Muhammad Asad:

Translation:
hence, remain thou patient in adversity - for, verily, God’s promise always comes true - and ask forgiveness for thy sins, and extol thy Sustainer’s glory and praise by night and by day. 38
Commentary:
38  According to all classical commentators, the above passage is addressed in the first instance to the Prophet and, through him, to every believer. As regards the Prophet himself, see note 41 on the last sentence of 24:31.