Lu'lu' wal-Marjan

The two rak‘ahs after ‘Asr were specific to you, sallallahu alayhi wa sallam. For the ummah, you prohibited performing voluntary (nafl) prayers after ‘Asr. (Secret:) The Prophet sallallahu alayhi wa sallam forbade performing prayer after ‘Asr, but due to the delegation of ‘Abd al-Qays, the two sunnah rak‘ahs after Dhuhr were missed, so he performed them after ‘Asr. From this, it is understood that the time after ‘Asr is, in reality, a time of prohibition (nahi), and performing any prayer in it is forbidden. However, if there is a prayer with a specific cause (sababi), it may be performed, such as a missed (qada) prayer, funeral prayer (salat al-janazah), or greeting the mosque (tahiyyat al-masjid), etc. As for the regularity (perpetual performance) of these two rak‘ahs, this was a particularity (khasiyyah) of the Prophet sallallahu alayhi wa sallam, which is present in the narration of Sayyidah ‘A’ishah radi Allahu anha, that it was the blessed habit of the Prophet sallallahu alayhi wa sallam that when he performed an action once, he would then persist in it.