It is narrated from Sayyiduna Samurah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever prays the Fajr prayer is under the protection of Allah, so let not Allah demand anything from you concerning (a violation of) His protection."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6887