Sahih al-Bukhari 556
Book 9: Times of the Prayers · Narrated by Abu Huraira
Arabic
حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا شَيْبَانُ، عَنْ يَحْيَى، عَنْ أَبِي سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا أَدْرَكَ أَحَدُكُمْ سَجْدَةً مِنْ صَلاَةِ الْعَصْرِ قَبْلَ أَنْ تَغْرُبَ الشَّمْسُ فَلْيُتِمَّ صَلاَتَهُ، وَإِذَا أَدْرَكَ سَجْدَةً مِنْ صَلاَةِ الصُّبْحِ قَبْلَ أَنْ تَطْلُعَ الشَّمْسُ فَلْيُتِمَّ صَلاَتَهُ ".
English translation
Narrated Abu Huraira:Allah's Messenger (ﷺ) said, "If anyone of you can get one rak`a of the `Asr prayer before sunset, he should complete his prayer. If any of you can get one rak`a of the Fajr prayer before sunrise, he should complete his prayer
Reference: Sahih al-Bukhari 556, Book of Times of the Prayers. English translation by Dr. Muhammad Muhsin Khan.