Allah's Messenger (ﷺ) used to offer thirteen rak`at in the night prayer and on hearing the Adhan for the morning prayer, he used to offer two light rak`at.
Sahih al-Bukhari Book 19, Hadith 43
← Previous Hadith The Prophet (ﷺ) was never more regular and particular in offering any Nawafil than the two rak`at (Sunna) of the Fajr prayer.

Sahih al-Bukhari Book 19, Hadith 42 Next Hadith → The Prophet (p.b.u.h) used to make the two rak`at before the Fajr prayer so light that I would wonder whether he recited Al-Fatiha (or not).

Sahih al-Bukhari Book 19, Hadith 44