Al-Bara' b. 'Azib reported:
This verse was revealed (in this way): Guard the prayers and the 'Asr prayer. We recited it (in this very way) so long as Allah desired. Allah, then, abrogated it and it was revealed: Guard the prayers, and the middle prayer. A person who was sitting with Shaqiq (one of the narrators in the chain of transmitters) said: Now it implies the 'Asr prayer. Upon this al-Bara' said: I have already informed you how this (verse) was revealed and how Allah abrogated it, and Allah knows best.