Humaid bin 'Abdur Rahman حميد بن عبد الرحمن بن عوف الزهرى · The Book of Oaths and Vows

"By my father and by my mother." He said: "Allah forbids you to swear by your forefathers." 'Umar said: "By Allah, I never swore by them again, whether saying it for myself or reporting it of others."