Musnad Abu Ya'la al-Mawsili 118:35

'Abd al-Rahman ibn al-Mutawakkil narrated to us, Fudayl ibn Sulayman al-Numayri narrated to us, 'Abd al-Rahman ibn Ishaq al-Madani narrated to us, from al-Zuhri, from Anas ibn Malik, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "I asked Allah for the *lahin* (those who died in a state of innocence/childhood) from the offspring of mankind, and He granted them to me."