Musnad Ahmad 31:614

Uthman ibn Umar narrated to us, Malik ibn Mighwal informed us, from Atiyyah al-Awfi, from Abu Sa’id al-Khudri, that the Messenger of Allah (may Allah bless him and grant him peace) said: "Indeed, a man from my nation will intercede for a large group of people, and they will enter Paradise by his intercession. And a man will intercede for a tribe of people, and they will enter Paradise by his intercession. And a man will intercede for a man and his household, and they will enter Paradise by his intercession."