Musannaf Ibn Abi Shayba 13:3172

Abu Bakr narrated to us, he said: Ghundar narrated to us, from Shu'bah, from 'Umarah ibn Abi Hafsah, who said: Two men disputed before al-Hasan. He [one of them] said to him: "Make him swear an oath regarding a right that belonged to his father, [even though] he did not witness his father [possessing it]." He [al-Hasan] said: "And would anyone who possesses intellect swear an oath regarding this?"