It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that once a man asked the Prophet (peace and blessings be upon him): "O Messenger of Allah! What do you command us regarding the night prayer?" He replied: "You should pray in pairs of two rak‘ahs, and when you fear that morning is near, then add one rak‘ah to those two. That will suffice as witr for all the prayers you have offered during the night."