A man who begins praying at night and dawn comes upon him

Ibn Awn said: I asked Ibrahim: If a person begins the witr prayer in the very last part of the night, what is the ruling? He said: He should say the opening takbir and recite; when dawn breaks, he should complete one rak'ah, then join another rak'ah to it, and these two rak'ahs will become the two sunnah rak'ahs of Fajr.

Ibn Awn said: I mentioned that to Muhammad bin Sirin, and he said: I do not know what this is.

Ja'far bin Burqan said: I said to Maymun: I recite a long surah in the night prayer and the morning comes upon me during it, until it becomes light; may I then join another rak'ah to it and make this prayer the sunnah of Fajr? He said: Yes, you may.

Mujahid said: If a person wishes, he may begin a prayer at the end of the night and lengthen its rak'ah, until when morning comes he bows; then he joins another rak'ah to it, and then counts these two rak'ahs as the two sunnah rak'ahs of Fajr.