Musannaf Ibn Abi Shayba 21:618

Waki’ narrated to us, from al-A’mash, from Abu Bakr ibn ‘Amr ibn ‘Utbah, from Ibn Hudhayfah, from his father, that the Prophet, may Allah bless him and grant him peace, when he would supplicate for a man, it would reach him, and reach his children, and his children’s children.