It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that Sayyiduna Umar (may Allah be pleased with him) asked the Prophet (peace and blessings of Allah be upon him): If a person becomes impure by choice, can he sleep in that state? The Prophet of Allah (peace and blessings of Allah be upon him) said: "Yes, he should perform ablution and then sleep." Nafi' says that whenever Sayyiduna Ibn Umar (may Allah be pleased with them both) intended to do such a thing, he would perform ablution as for prayer, leaving only the feet.