That Messenger of Allah ﷺ came to her in a happy mood with his features glittering with joy, and said, "Have you not heard what the Qaif has said about Zaid and Us-ama? He saw their feet and remarked. These belong to each other." (i.e. They are father and son.)
أَنَّ رَسُولَ اللَّهِ ﷺ دَخَلَ عَلَيْهَا مَسْرُورًا تَبْرُقُ أَسَارِيرُ وَجْهِهِ فَقَالَ أَلَمْ تَسْمَعِي مَا قَالَ الْمُدْلِجِيُّ لِزَيْدٍ وَأُسَامَةَ وَرَأَى أَقْدَامَهُمَا إِنَّ بَعْضَ هَذِهِ الأَقْدَامِ مِنْ بَعْضٍ