عَنِ ابْنِ عَبَّاسٍ قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُصُّ أَوْ يَأْخُذُ مِنْ شَارِبِهِ وَكَانَ إِبْرَاهِيمُ خَلِيلُ الرَّحْمَنِ صَلَوَاتُ الرَّحْمَنِ عَلَيْهِ يَفْعَله. رَوَاهُ التِّرْمِذِيّ
Translation

She told that a woman made a sign from behind a curtain to indicate that she had a letter for God's messenger. The Prophet closed his hand saying, “I do not know whether this is a man’s or a woman’s hand," and when she declared that it was a woman’s he said, “If you were a woman you would make a difference to your nails," meaning with henna. Abu Dawud and Nasa'i transmitted it.