1119/1 - ‘Ali ibn Abi Tālib (may Allah be pleased with him) reported: “The Prophet (may Allah’s peace and blessings be upon him) used to offer four Rak‘ahs before the ‘Asr prayer, separating between them with Taslīm upon the close angels and the Muslims and believers who followed them (i.e. Tashahhud).” [Narrated by Al-Tirmidhi; and he classified it as Hasan (sound)]
1120/2 - Ibn ‘Umar (may Allah be pleased with him and his father) reported that the Prophet (may Allah’s peace and blessings be upon him) said: “May Allah have mercy upon a person who offers four Rak‘ahs before the ‘Asr prayer.” [Narrated by Abu Dāwūd and Al-Tirmidhi, who classified it as Hasan (sound)]
1121/3 - ‘Ali ibn Abi Tālib (may Allah be pleased with him) reported that the Prophet (may Allah’s peace and blessings be upon him) used to offer two Rak‘ahs before the ‘Asr prayer. [Narrated by Abu Dāwūd, with an authentic Isnād] [15]
1) They point out the Prophet’s guidance concerning the Sunnah of the ‘Asr prayer. It is an ordinary supererogatory prayer, not a Rātibah (regular) one.
2) Performing four Rak‘ahs before the ‘Asr prayer leads to winning Allah’s mercy.
3) The four Rak‘ahs are to be separated with Tashahhud, not Taslīm. That is the prescribed Prophetic guidance.
Authentic Hadīths mention that the Sunnah before the ‘Asr prayer is four Rak‘ahs. As for the Hadīth in which ‘Ali (may Allah be pleased with him) reported that the Prophet (may Allah’s peace and blessings be upon him) used to perform two Rak‘ahs before the ‘Asr prayer, it is weak, given that it contradicts the authentic Hadīths.