كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
5  
The Book of Mosques and Places of Prayer
(9)
Chapter: The permissibility of carrying children during prayer, and their garments are regarded as being pure until it is realized that they are impure. Few actions will not invalidate the prayer, and the same applies if several such actions are done but are done separately
(9)
باب جَوَازِ حَمْلِ الصِّبْيَانِ فِي الصَّلاَةِ ‏
Sahih Muslim 543 d

Abu Qatada reported:

As we were sitting in the mosque, the Messenger of Allah (ﷺ) came to us, and the rest of the hadith is the same except that he made no mention that he led people in this prayer.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا لَيْثٌ، ح قَالَ وَحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا أَبُو بَكْرٍ الْحَنَفِيُّ، حَدَّثَنَا عَبْدُ الْحَمِيدِ بْنُ جَعْفَرٍ، جَمِيعًا عَنْ سَعِيدٍ الْمَقْبُرِيِّ، عَنْ عَمْرِو بْنِ سُلَيْمٍ الزُّرَقِيِّ، سَمِعَ أَبَا قَتَادَةَ، يَقُولُ بَيْنَا نَحْنُ فِي الْمَسْجِدِ جُلُوسٌ خَرَجَ عَلَيْنَا رَسُولُ اللَّهِ صلى الله عليه وسلم ‏.‏ بِنَحْوِ حَدِيثِهِمْ غَيْرَ أَنَّهُ لَمْ يَذْكُرْ أَنَّهُ أَمَّ النَّاسَ فِي تِلْكَ الصَّلاَةِ ‏.‏
Reference : Sahih Muslim 543d
In-book reference : Book 5, Hadith 55
USC-MSA web (English) reference : Book 4, Hadith 1110
  (deprecated numbering scheme)