Sayyidah Aisha (may Allah be pleased with her) narrates that when the Messenger of Allah (peace and blessings be upon him) was in a state of major ritual impurity (janabah) and intended to sleep, he would wash his private parts and perform ablution as he did for prayer.

Sayyiduna Ibn Umar (may Allah be pleased with them) narrates that Sayyiduna Umar (may Allah be pleased with him) asked the Messenger of Allah (peace and blessings be upon him), "Can any of us sleep while in a state of major ritual impurity (janabah)?" He replied, "Yes, you can sleep in a state of janabah after performing ablution (wudu)."

Sayyiduna Abdullah bin Umar (may Allah be pleased with them) narrated that Sayyiduna Umar (may Allah be pleased with him) said to the Prophet (peace and blessings of Allah be upon him) that he sometimes needed to perform ghusl (ritual bath) at night. So the Messenger of Allah (peace and blessings of Allah be upon him) said to him: Perform ablution, wash your private parts, and then go to sleep.

Sayyiduna Anas bin Malik (may Allah be pleased with him) narrated that the Prophet (peace and blessings of Allah be upon him) visited all his noble wives in a single night, and at that time he had nine wives.