Be not a witness against thy neighbour without cause,.... Unless forced unto it, except there is some urgent reason for it; not upon any trivial account, or in any frivolous matter; never appear forward and eager to bear witness against him, and, whenever obliged to it, be not a false witness, but speak truth, whether thy neighbour be a friend or a foe;
and deceive [not] with thy lips; by bearing a false testimony, the judge, thy neighbour and thyself; for though men may be deceived, God cannot: or, shouldest thou do so, "thou wouldest break" and cut him to pieces "with thy lips" x; which is the sense of the words according to R. Judah, as Ben Melech relates.
x והפיתית בשפתיך "et ne atteras labiis tuis", Vatablus; "et ne comminuas eum labiis tuis", Syriac version.