Translation:

2. O ye who believe! why say ye that which ye do not?

Notes (Tafseer)

5432. At Uhud there was some disobedience and therefore breach of discipline. People had talked much, but had failed to back up their resolution in words with firmness in action. See n. 442 to iii. 121. But on all occasions when men's deeds are not commensurate with their words, their conduct is odious in the sight of Allah, and it is only due to Allah's Mercy if they are saved from disaster.