It was narrated from 'Aishah that: A woman reached out her hand (to give) a letter to the Prophet [SAW], and he withdrew his hand. She said: O Messenger of Allah, I reached out my hand (to give you) a letter and you did not take it. He said: I did not know whether it was the hand of a woman or a man. She said: It is the hand of a woman. He said: If you were a woman, you would change your nails (by dyeing them with Henna).