Musnad Ahmad 27:1271

Abu Abd al-Rahman Abdullah ibn Yazid narrated to us, Haywah narrated to us, Abu Uthman al-Walid narrated to us, from Abdullah ibn Dinar, from Ibn Umar, from the Messenger of Allah, may Allah bless him and grant him peace, that he said: "Indeed, the best of righteousness is for a man to maintain ties with the people his father loved."