Chapter: Whoever got (or was able to offer) one Rak'a of the Fajr prayer (in time). [One Rak'a means, one standing, one bowing, and two prostrations].
Narrated Abu Huraira:Allah's Messenger (ﷺ) said, "Whoever could get one rak`a (of the Fajr prayer) before sunrise, he has got the (morning) prayer and whoever could get one rak`a of the `Asr prayer before sunset, he has got the (`Asr) prayer."
Reference
Sahih al-Bukhari 579
In-book reference
Book 9, Hadith 55
USC-MSA web (English)
Vol. 1, Book 10, Hadith 553
Translation by Dr. M. Muhsin Khan · Language: EN
Sahih
Arabic Text
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ عَطَاءِ بْنِ يَسَارٍ، وَعَنْ بُسْرِ بْنِ سَعِيدٍ، وَعَنِ الأَعْرَجِ، يُحَدِّثُونَهُ عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَنْ أَدْرَكَ مِنَ الصُّبْحِ رَكْعَةً قَبْلَ أَنْ تَطْلُعَ الشَّمْسُ فَقَدْ أَدْرَكَ الصُّبْحَ، وَمَنْ أَدْرَكَ رَكْعَةً مِنَ الْعَصْرِ قَبْلَ أَنْ تَغْرُبَ الشَّمْسُ فَقَدْ أَدْرَكَ الْعَصْرَ ".