´It was narrated from Mahmud bin Labid, from some men among his people who were of the Ansar, that the Messenger of Allah (ﷺ) said:` "The more you delay Fajr, the greater the reward."
Hadith ReferenceSunan an-Nasa'i / The Book of the Times (of Prayer) / Hadith: 550
Hadith Gradingالألبانی:صحيح الإسناد | زبیر علی زئی:إسناده صحيح