It is narrated from Hazrat Aisha that sometimes the Prophet (peace be upon him) would be in a state of major ritual impurity (janabah) at night by choice. Hazrat Bilal would come to inform about the Fajr prayer, so the Prophet (peace be upon him) would get up and perform ghusl, and I would see that water was dripping from his skin and hair, and I would hear his recitation, and on that day the Prophet (peace be upon him) would be fasting.