It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever prays the Fajr prayer in congregation, then sits remembering Allah until the sun rises, then stands and prays two rak'ahs, returns with the reward of a Hajj and an Umrah."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7710