Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) was praying at night, and a woman was also performing prayer with him. When he noticed her, he said: "If you wish, you may lie down." She said: "I am still energetic." The Prophet (peace and blessings of Allah be upon him) said: "You are not like me; the coolness of my eyes is in the prayer."