Musnad Ahmad 8:61

'Abd al-Razzaq narrated to us, Sufyan informed us, from 'Asim, Abu 'Uthman al-Nahdi narrated to me, he said: I heard Ibn Malik saying: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever claims to be the son of someone other than his father while he knows it, then Paradise is forbidden to him."