Narrated `Aisha: Allah's Apostle 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.
Hadith Referenceصحيح البخاري / كتاب التهجد / 1164
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة