Musnad Ahmad 920:13

Abdullah narrated to us, Abu al-Rabi’ al-‘Ataki Sulayman ibn Dawud al-Zahrani narrated to us, al-Mu’tamir ibn Sulayman narrated to us, he said: I heard my father mentioning, from Raqabah. And Abdullah narrated to us, he said: Muhammad ibn Abi Bakr al-Muqaddami narrated to me, al-Mu’tamir narrated to us, from his father, from Raqabah. And Abdullah narrated to us, he said: Suwayd ibn Sa’id narrated to me. And Abdullah narrated to us, he said: Muhammad ibn Ahmad ibn Khalid al-Wasiti narrated to me, they said: al-Mu’tamir narrated to us, from his father, from Raqabah. They all said: From Abu Ishaq, from Sa’id ibn Jubayr, from Ibn Abbas, from Ubayy ibn Ka’b, from the Prophet, peace and blessings of Allah be upon him: "The boy whom al-Khidr killed was created a disbeliever." Abu al-Rabi’ added in his narration: "And had he reached maturity, he would have burdened his parents with transgression and disbelief."