Bulugh al-Maram, Book 6, Hadith 7 (In-Book)

Ibn ’Abbas (RAA) narrated, The Messenger of Allah came across some riders at ar-Rauha’ (a place near Madinah). He asked them, “Who are you?" They replied, ‘Who are you?’ He replied, "I am the Messenger of Allah." A woman then lifted up a boy, and asked the Prophet, Will this boy be rewarded for Hajj? The Messenger of Allah replied, “Yes, and you too will be Rewarded.” Related by Muslim.

وَعَنْ اِبْنِ عَبَّاسٍ رَضِيَ اَللَّهُ عَنْهُمَا; { أَنَّ اَلنَّبِيَّ ‏- صلى الله عليه وسلم ‏-لَقِيَ رَكْبًا بِالرَّوْحَاءِ فَقَالَ: " مَنِ اَلْقَوْمُ? " قَالُوا: اَلْمُسْلِمُونَ.‏ فَقَالُوا: مَنْ أَنْتَ? قَالَ: " رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-" فَرَفَعَتْ إِلَيْهِ اِمْرَأَةٌ صَبِيًّا.‏ فَقَالَتْ: أَلِهَذَا حَجٌّ? قَالَ: " نَعَمْ: وَلَكِ أَجْرٌ " } رَوَاهُ مُسْلِمٌ 1‏.‏ ‏1 ‏- صحيح.‏ رواه مسلم ( 1336 )‏، والروحاء: مكان على ستة وثلاثين ميلا من المدينة.‏

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also referenced under: Book 6, Hadith 733 (English)