Sayyiduna Ibn Umar (may Allah be pleased with them both) said: A man asked the Messenger of Allah (peace and blessings be upon him) about the night prayer (Tahajjud), so the Messenger of Allah (peace and blessings be upon him) said:“(It) is in sets of two rak‘ahs. When one of you fears that morning is approaching, let him pray one rak‘ah as Witr, and it will make all his prayer odd-numbered.”