(30) باب مَنْ أَدْرَكَ رَكْعَةً مِنَ الصَّلاَةِ فَقَدْ أَدْرَكَ تِلْكَ الصَّلاَةَ
A'isha reported:
The Messenger of Allah (ﷺ) said: He who finds a prostration before sunset or at dawn (prayer) before the rising (of the sun) he in fact finds that (prayer), and prostration implies a rak'ah. (DE)
Reference (DE): Sahih Muslim 609 (DE)
In-book reference (DE): Book 5, Hadith 208 (DE)
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1264 (DE)