Hadith 2510
وَعَنْهُ قَالَ: إِنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَقِيَ رَكْبًا بِالرَّوْحَاءِ فَقَالَ: «مَنِ الْقَوْمُ؟» قَالُوا: الْمُسْلِمُونَ. فَقَالُوا: مَنْ أَنْتَ؟ قَالَ: «رَسُولُ اللَّهِ» فَرَفَعَتْ إِلَيْهِ امْرَأَةٌ صَبِيًّا فَقَالَتْ: أَلِهَذَا حَجٌّ؟ قَالَ: «نَعَمْ وَلَكِ أَجَرٌ» . رَوَاهُ مُسْلِمٌ
He told of the Prophet meeting some riders at ar-Rauha’ (A place between thirty and forty miles from Medina on the way to Mecca) and asking who they were. They replied that they were Muslims and asked who he was. When he said that he was God's messenger a woman lifted up a boy to him and asked whether the child could be credited with having performed the pilgrimage, to which he replied, “Yes, and you will have a reward.” Muslim transmitted it.