Musnad Ahmad 1060:14

Yahya ibn Ishaq narrated to us, Ibn Lahi'ah informed us, from Ubayd Allah ibn Abi Ja'far, from Amr ibn al-Aswad, from Abu Ayyub, who said: And Ali ibn Ishaq narrated to us, Abdullah informed us, Ibn Lahi'ah informed us, from Ubayd Allah ibn Abi Ja'far, who narrated to him, from Amr ibn al-Aswad, from Abu Ayyub, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The hand of Allah is with the judge when he judges, and the hand of Allah is with the divider when he divides."