Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: Sayyiduna Umar bin Khattab (may Allah be pleased with him) asked the Prophet Muhammad (peace and blessings be upon him): Can any one of us sleep in a state of janabah (major ritual impurity)? The Prophet Muhammad (peace and blessings be upon him) said: Yes, when he performs ablution (wudu), (then he can sleep).