It is narrated from Umm al-Mu'minin Sayyida Aisha (may Allah be pleased with her) that a woman extended her hand from behind a curtain to hand a book to the Messenger of Allah (peace and blessings be upon him). The Prophet (peace and blessings be upon him) withdrew his hand and said: "I do not know whether this is the hand of a man or a woman." She said: "It is the hand of a woman." The Prophet (peace and blessings be upon him) said: "If you were a woman, you would have colored your nails with henna."