It is narrated from Sayyida Aisha (may Allah be pleased with her) that one night the Prophet (peace and blessings be upon him) became restless and his sleep was disturbed. He (peace be upon him) said: "If only some righteous man from among my companions would come and stand guard for me." Suddenly, we heard the sound of weapons, so the Prophet (peace be upon him) asked: "Who is it?" He replied: Sa'd. Then Sayyiduna Sa'd (may Allah be pleased with him) said: O Messenger of Allah! I have come to stand guard for you. Then the Prophet (peace be upon him) slept peacefully until we heard the sound of his snoring.