The Book of the Times (of Prayer)
6/28. Chapter:
Whoever Catches Up With A Rak'ah Of The Subh Prayer
Sunan an-Nasai
أَخْبَرَنَا مُحَمَّدُ بْنُ رَافِعٍ، قَالَ حَدَّثَنَا زَكَرِيَّا بْنُ عَدِيٍّ، قَالَ أَنْبَأَنَا ابْنُ الْمُبَارَكِ، عَنْ يُونُسَ بْنِ يَزِيدَ، عَنِ الزُّهْرِيِّ، عَنْ عُرْوَةَ، عَنْ عَائِشَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " مَنْ أَدْرَكَ رَكْعَةً مِنَ الْفَجْرِ قَبْلَ أَنْ تَطْلُعَ الشَّمْسُ فَقَدْ أَدْرَكَهَا وَمَنْ أَدْرَكَ رَكْعَةً مِنَ الْعَصْرِ قَبْلَ أَنْ تَغْرُبَ الشَّمْسُ فَقَدْ أَدْرَكَهَا " .
It was narrated from 'Aishah that the Prophet (ﷺ) said: "Whoever catches up with a Rak'ah of Fajr before the sun rises, then he has caught up with it; and whoever catches up with a Rak'ah of 'Asr before the sun sets, then he has caught up with it."
Reference : Sunan an-Nasa'i 551In-book reference : Book 6, Hadith 58English translation : Vol. 1, Book 6, Hadith 552