Narrated from Sayyiduna Ibn Umar (may Allah be pleased with them) that Sayyiduna Umar bin Khattab (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)?" The Prophet (peace and blessings be upon him) replied: "Yes! When any of you is in a state of janabah, he should perform ablution (wudu) and then sleep."