Hadith 256

Bulugh al-Maram

Book 2: The Book of Prayer
وَلِمُسْلِمٍ : { كَانَ إِذَا طَلَعَ اَلْفَجْرُ لَا يُصَلِّي إِلَّا رَكْعَتَيْنِ خَفِيفَتَيْنِ } 1‏
Muslim has:

'He never prayed after the break of dawn except two light Rak'at.'