Countenance - Rather, show partiality to a man's cause because he is poor (compare Leviticus 19:15).
These four commands, addressed to the conscience, are illustrations of the ninth commandment, mainly in reference to the giving of evidence in legal causes. Compare 1-Kings 21:10; Acts 6:11.

Neither shalt thou countenance a poor man in his cause - The word דל dal, which we translate poor man, is probably put here in opposition to רבים rabbim, the great, or noble men, in the preceding verse: if so, the meaning is, Thou shalt neither be influenced by the great to make an unrighteous decision, nor by the poverty or distress of the poor to give thy voice against the dictates of justice and truth. Hence the ancient maxim, Fiat Justitia, Ruat Coelum. "Let justice be done, though the heavens should be dissolved."

Neither shalt thou countenance a poor man in his cause. Because he is a poor man, and for that reason endeavour to carry his cause for him, right or wrong, from a foolish pity to him as a poor man, and from an affectation of gaining the applause of people on that account; or "thou shalt not honour" or "adorn" a poor man (u), by a set speech in favour of his cause, though wrong, dressed up in the best manner, and set off with all the colourings of art, to make it appear in the most plausible manner; the law is against respect of persons, as not the person of the rich, so neither is the person of the poor to be accepted, but the justice of their cause is to be regarded; so the Targum of Jonathan,"the poor that is guilty in his judgment or cause, his face (or person) thou shalt not accept to have pity on him, for no person is to be accepted in judgment.''
(u) "non honorabis", Pagninus, Vatablus, Drusius, Cartwright; "non decorabis", Montanus; "ne ornes", Tigurine version; "ne honorato", Junius & Tremellius; "ne ornato", Piscator.

countenance--adorn, embellish--thou shalt not varnish the cause even of a poor man to give it a better coloring than it merits.