Musnad Abu Ya'la al-Mawsili 120:4

Amr ibn Malik al-Basri narrated to us, al-Fudayl ibn Sulayman narrated to us, Abd al-Rahman ibn Ishaq al-Qurashi narrated to us, from Muhammad ibn al-Munkadir, from Anas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "I asked my Lord regarding the *lahin* (those who are unaware/innocent) from the offspring of mankind, and He granted them to me."