The Prophet ﷺ said, as far as I know (Musa was uncertain), "The young children of the Muslims are in Paradise, where Ibrahim takes care of them."
حدثنا موسى بن داود حدثنا عبد الرحمن بن ثابت عن عطاء بن قرة عن عبد الله بن ضمرة
عن النبي ﷺ فيما أعلم شك موسى قال ذراري المسلمين في الجنة يكفلهم إبراهيم عليه السلام
Saeed bin Mansur narrated it in his Sunan from Makhul as a mursal report, with the wording, "The children of the Muslims are green sparrows in the trees of Paradise, cared for by their father Ibrahim." Abu Bakr bin Abu Dawud narrated it in al-Bath from Abu Hurairah with the wording, "The children of the Muslims are cared for by Ibrahim." Suyuti noted in al-Jami al-Saghir that it is a sahih hadith.Suyuti also pointed to another version, "The children of the Muslims will be beneath the Throne on the Day of Resurrection, interceding and having intercession accepted on their behalf, for whoever has not reached twelve years of age. Whoever has reached thirteen years is accountable and has rights." Abu Bakr narrated it in al-Ghaylaniyyat, as Suyuti stated in al-Jami al-Saghir, and Ibn Asakir narrated it from Abu Umama, and Suyuti indicated that it is hasan. The isnad of this hadith is indeed hasan.