عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللهِ صلّى الله عليه وسلّم قَالَ: مَنْ أَدْرَكَ رَكْعَةً مِنَ الصَّلاَةِ فَقَدْ أَدْرَكَ الصَّلاَةَ.
Hazrat Abu Hurairahra narrated that Allah’s Messengersa said: “Whoever manages to catch a single rak‘ah of a [congregational] prayer has [effectively] caught that prayer.”
(Sahih al-Bukhari, Kitab mawaqiti s-salah, Bab man adraka min as-salati rak‘atan, Hadith 580)