Bava Batra 47 - Interested Party in a Lawsuit
A person is disqualified from testifying in a matter in which he has a material interest. Can a sharecropper testify on behalf of his employer concerning the land on which he is working?
If there is unharvested fruit in the field, he cannot testify. The sharecropper has a material interest, because if someone else should prove to be the real owner of the field, the sharecropper will not collect his full share of the unharvested fruit.
However, if there is no fruit in the field, he can testify. Though advancing his employer's cause might protect his own job as a sharecropper in this field, he knows that there are many other sharecropping jobs available to him. Moreover, he knows that his employer is under no obligation to continue to employ him. Therefore, his interest in the outcome of the case is negligible.