Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Sha’bi (may Allah have mercy on him) that Hazrat Shurayh used to demand an oath from both the absent and the present. The narrator says that I asked Hazrat ‘Amir, “What is your opinion if someone claims a debt upon my father, about which I have no knowledge—can I take an oath on it?” He replied, “Yes, you can take the oath.” Then both of them strongly rejected this. He said, “The oath should be referred to the one who knows more than you.” And Hazrat ‘Amir used to accept this oath.