عَنْ عَائِشَةَ أُمِّ الْمُؤْمِنِينَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ مَدَّتِ امْرَأَةٌ مِنْ وَرَاءِ السِّتْرِ بِيَدِهَا كِتَابًا إِلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ فَقَبَضَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يَدَهُ وَقَالَ مَا أَدْرِي أَيَدُ رَجُلٍ أَوْ يَدُ امْرَأَةٍ فَقَالَتْ بَلِ امْرَأَةٌ فَقَالَ لَوْ كُنْتِ امْرَأَةً لَغَيَّرْتِ أَظْفَارَكِ بِالْحِنَّاءِ
Lady Aisha (may Allah be pleased with her) narrates that a woman stretched out her hand towards the Messenger of Allah (peace and blessings be upon him) from behind a veil, but the Noble 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: Yes, I am a woman. The Prophet (peace and blessings be upon him) said: If you are a woman, you should have changed the color of your nails with henna.