It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Whoever performs ablution, then comes to the mosque and prays two rak'ahs before Fajr, then sits until he prays the Fajr prayer, his prayer that day will be written among the prayers of the righteous, and he will be written among the delegation of the Most Merciful."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7735