Musnad Abu Ya'la al-Mawsili 153:123

And from his father, that the Prophet (peace and blessings of Allah be upon him) heard Umar while he was saying, "And by my father, and by my father." So he said, "Indeed, Allah forbids you from swearing by your fathers." Umar said, "By Allah, I have not sworn by them since then, neither as a narrator nor as one repeating it."