Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Mughira and Hazrat Shabirma that Hazrat Abdullah bought a slave. When he brought him home, the slave developed a fever. He took the slave back to return him, and the dispute was brought before Hazrat Shabi (may Allah have mercy on him). He (may Allah have mercy on him) said to Hazrat Abdullah: Present witnesses that he concealed the defect of the slave from you. He (may Allah have mercy on him) said: I have no witnesses. Hazrat Shabi (may Allah have mercy on him) said to the other person: Swear an oath that you did not sell the slave while he was ill. That person said: I defer the oath to Abdullah. Hazrat Shabi (may Allah have mercy on him) decided that Abdullah should take the oath and said: You must swear an oath, otherwise the slave will be binding upon you.