Halakhah for Sanhedrin 53:18
והלכתא כוותיה דאביי והא איתותב ההיא רבי יוסי היא
Surely this refers to botha vain oath<span class="x" onmousemove="('comment',' E.g., an oath that a pillar of stone is made of stone, which is a needless oath. ');"><sup>18</sup></span>
Sefer HaChinukh
Not to have a sinner testify: That we not accept the testimony of a man who sins, and we not do anything on account of his testimony, as it is stated (Exodus 23:1), "do not place your hand with an evildoer to be a violent witness." And the explanation comes about this (Sanhedrin 27a), "Do not place an evildoer as a witness, do not place a violent one as a witness," meaning a violent person - to exclude violent people and thieves who are disqualified from testimony, as it is stated (Deuteronomy 19:16), "If a violent witness comes upon a man."
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