(30) باب مَنْ أَدْرَكَ رَكْعَةً مِنَ الصَّلاَةِ فَقَدْ أَدْرَكَ تِلْكَ الصَّلاَةَ
Abu Huraira reported the Messenger of Allah (ﷺ) as saying:
He who finds a rak'ah of the prayer, he in fact finds the prayer. (RU)
Reference (RU): Sahih Muslim 607 a (RU)
In-book reference (RU): Book 5, Hadith 205 (RU)
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1260 (RU)