(2) باب رَكْعَتَىِ الْفَجْرِ
Narrated 'Aishah:
The Messenger of Allah (ﷺ) was more particular about observing the supererogatory rak'ahs before the dawn prayer than about observing any of the other supererogatory prayers. (ID)
Reference (ID): Sunan Abi Dawud 1254 (ID)
In-book reference (ID): Book 5, Hadith 5 (ID)
English translation (ID): Book 5, Hadith 1249 (ID)