Sunan an-Nasa'i, Volume 3, Book 24, Hadith 2647 (DarusSalam) ⓘ
It was narrated that Ibn 'Abbas said: "A woman lifted up a child of hers from a howdah (litter) and said: 'O Messenger of Allah, is there Hajj for this one?' He said: 'Yes, and you will be rewarded.'''(sahih)
أَخْبَرَنَا مَحْمُودُ بْنُ غَيْلاَنَ، قَالَ حَدَّثَنَا بِشْرُ بْنُ السَّرِيِّ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ مُحَمَّدِ بْنِ عُقْبَةَ، عَنْ كُرَيْبٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ رَفَعَتِ امْرَأَةٌ صَبِيًّا لَهَا مِنْ هَوْدَجٍ فَقَالَتْ يَا رَسُولَ اللَّهِ أَلِهَذَا حَجٌّ قَالَ " نَعَمْ وَلَكِ أَجْرٌ " .
also referenced under: Hadith 2646 (Reference) & Book 24, Hadith 0 (In-Book)