(60) باب وَقْتِ رَكْعَتَىِ الْفَجْرِ وَذِكْرِ الاِخْتِلاَفِ عَلَى نَافِعٍ
It was narrated from Abdullah bin Umar, from Hafsah, that:
The Messenger of Allah (ﷺ) used to pray two rak'ahs when dawn had broken. (ID)
Reference (ID): Sunan an-Nasa'i 1775 (ID)
In-book reference (ID): Book 20, Hadith 178 (ID)
English translation (ID): Vol. 2, Book 20, Hadith 1776 (ID)