It was narrated from Abu Hurairah that:The Messenger of Allah said: "Whoever catches one Rak'ah of the 'Asr before the sun sets, then he has caught it, and whoever catches one Rak'ah of the Subh before the sun rises, then he has caught it
Hadith No. 699
Sunan Ibn Majah
Gradings:
Al-Albani:
Sahih
Muhammad Fouad Abd al-Baqi:
Sahih
Zubair Ali Zai:
Sahih - Bukhari And Muslim