Ali Radi Allahu Anhu narrated

✦ Ali Radi Allahu Anhu narrated The Prophet Sallallahu Alaihi wasallam used to pray four Rak'ah before Al-Asr

Jamia Tirmizi, Book 2, Hadith 429-Hasan

✦ Ibn Umar Radi Allahu Anhu narrated that The Prophet Sallallahu Alaihi wasallam said: May Allah have mercy upon a person who prays four before Al-Asr.

Jamia Tirmizi, Book 2, Hadith 430-Hasan

✦ It was Narrated from tamim dari may ALLAH be pleased with him that the Prophet Peace be upon him said The first thing for which A person will be brought to a account on the Day of Resurrection will be his prayer (Salah) . If it is complete then the voluntary (Nawafil) prayer will also be recorded for him (As an increase) If it is not complete then Allah will say to his Angels Look and see wheather you find any voluntary (Nawafil) prayer for my slave and take them to make up what is lacking from his obligatory (farz) prayers then All his deeds will be recokened in like manner

Sunan Ibn Majah, Volume 1, #1426 - Sahih