The Book of the Times (of Prayer)
6/24. Chapter:
The Beginning Of The Time For Subh
Sunan an-Nasai
أَخْبَرَنَا إِبْرَاهِيمُ بْنُ هَارُونَ، قَالَ حَدَّثَنَا حَاتِمُ بْنُ إِسْمَاعِيلَ، قَالَ حَدَّثَنَا جَعْفَرُ بْنُ مُحَمَّدِ بْنِ عَلِيِّ بْنِ الْحُسَيْنِ، عَنْ أَبِيهِ، أَنَّ جَابِرَ بْنَ عَبْدِ اللَّهِ، قَالَ صَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم الصُّبْحَ حِينَ تَبَيَّنَ لَهُ الصُّبْحُ .
Ja'far bin Muhammad bin 'Ali bin Al-Husain narrated from his father, that Jabir bin 'Abdullah said: "The Messenger of Allah (ﷺ) prayed Subh as soon as he was certain the dawn had appeared."
Reference : Sunan an-Nasa'i 543In-book reference : Book 6, Hadith 50English translation : Vol. 1, Book 6, Hadith 544