It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that a man from the desert people asked the Prophet (peace and blessings be upon him) about the night prayer, and he (peace and blessings be upon him) gestured with his finger like this and said: "It is two by two rak'ahs, and the witr is one rak'ah in the last part of the night."