Musnad Ahmad 1302:16

'Abd al-Razzaq narrated to us, Sufyan informed us, from 'Ata' ibn al-Sa'ib, from Abu 'Abd al-Rahman al-Sulami, who said: There was a man among us—then he mentioned the hadith—he said: So he traveled to Abu al-Darda', and he said: I heard the Prophet, peace and blessings of Allah be upon him, saying: "The father is the middle of the gates of Paradise."