Sunan an-Nasa'i, Hadith 2649 ⓘ
It was narrated from Ibn 'Abbas that: the Messenger of Allah passed by a woman when she was in her seclusion and had a child with her. She said: "Is there Hajj for this one?'' He said: "Yes, and you will be rewarded.''(sahih)
أَخْبَرَنَا سُلَيْمَانُ بْنُ دَاوُدَ بْنِ حَمَّادِ بْنِ سَعْدٍ ابْنُ أَخِي، رِشْدِينَ بْنِ سَعْدٍ أَبُو الرَّبِيعِ وَالْحَارِثُ بْنُ مِسْكِينٍ قِرَاءَةً عَلَيْهِ وَأَنَا أَسْمَعُ، عَنِ ابْنِ وَهْبٍ، قَالَ أَخْبَرَنِي مَالِكُ بْنُ أَنَسٍ، عَنْ إِبْرَاهِيمَ بْنِ عُقْبَةَ، عَنْ كُرَيْبٍ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم مَرَّ بِامْرَأَةٍ وَهِيَ فِي خِدْرِهَا مَعَهَا صَبِيٌّ فَقَالَتْ أَلِهَذَا حَجٌّ قَالَ " نَعَمْ وَلَكِ أَجْرٌ " .
also referenced under: Book 24, Hadith 0 (In-Book) & Volume 3, Book 24, Hadith 2650 (DarusSalam)