Musnad Ahmad 25:696

'Abd al-Razzaq narrated to us, he said: Sufyan informed us, from Mansur, from Salim ibn Abi al-Ja'd, from Kurayb, the freed slave of Ibn 'Abbas, from Ibn 'Abbas, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "If one of them, when he approaches his wife, says: 'In the name of Allah, O Allah, keep Satan away from me and keep Satan away from what You provide for me,' then a child is born between them, Satan will never harm him."