رَكْعَتَا الْفَجْرِ خَيْرٌ مِنَ الدُّنْيَا وَمَا فِيهَا
Translation: The two rak‘ahs of Fajr are better than the world and all it contains.
This narration in Sahih Muslim supports the special status of the Fajr Sunnah; the Hanafi rule discourages additional voluntary prayer after true dawn.