Imam Al-Nawawi’s Riyad-us-Saliheen
Chapter 200
Sunnah of the ‘Asr Prayer
1119. `Ali bin Abu Talib (May Allah be pleased with him)reported: The Prophet (sallallaahu alayhi wa sallam) used to perform four Rak`ah before the `Asr prayer, separating them with Taslim (i.e., offering blessings) on the favourite angels who are near Allah’s proximity and the Muslims and the believers who come after them.
[At-Tirmidhi].
1120. Ibn `Umar (May Allah be pleased with them) reported: The Prophet (sallallaahu alayhi wa sallam) said, “May Allah have mercy on a man who performs four Rak`ah before the `Asr prayer.”
[Abu Dawud and At-Tirmidhi].
1121. `Ali bin Abu Talib (May Allah be pleased with him) reported: The Prophet (sallallaahu alayhi wa sallam) used to perform two Rak`ah before the `Asr prayer.
[Abu Dawud].
AbdurRahman.Org 