Sunan an-Nasa'i 642
سنن النسائي#642SahihIt was narrated from Anas that someone asked the Messenger of Allah (S.A.W) about the time of Subh. The Messenger of Allah (S.A.W) commanded Bilal to call the Adhan when dawn broke. Then the next day he delayed Fajr until it was very light, then he told him to call the Adhan and he prayed. Then he said:"This is the time for the prayer
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih Isnaad
Al-AlbaniSahih Isnaad
Zubair Ali ZaiHasan
In-book reference: 7:17