פירוש על ויקרא 19:15

לא תעשו עול במשפט YE SHALL NOT DO INJUSTICE IN JUDGMENT — This teaches us that the judge who perverts judgment is called an "unjust person" (עַוָּל), hateful and detested, doomed to destruction, and an abomination. He is rightly called thus for the unjust person (עַוָּל) is called by Scripture "abomination", as it is said (Deuteronomy 25:16) "For all that do [such things] all that do injustice (עַוָּל=עֹשֵׂה עָוֶל) are an abomination (תועבה) unto the Lord thy God”. The abomination (תועבה), on its part, is called by Scripture חרם and שקץ, as it is said (Deuteronomy 7:26) "Neither shalt thou bring an abomination (תועבה) into thine house, lest thou be a doomed thing (חרם) like it; but thou shall regard it as שקץ.

Now the Torah addresses the judges who are charged with dispensing fair judgment. לא תעשו עול במשפט, a warning not to relate sternly to one litigant while being lenient towards his opponent. Do not allow one litigant to sit down while his opponent is required to remain standing upright. This is followed by admonitions applicable to different levels of leadership in the people and the spirit of jealousy which often prevails between competing layers of the bureaucracy. Examples are: Doeg badmouthing David so as to gain favour with the king. (Samuel I 22,9) From such admonitions it is only a small step to warn against badmouthing people generally, especially when it even involves slander. The sin of slandering is considered so serious by the prophet Ezekiel that he describes it as being equal to bloodshed (Ezekiel 22,9)

לא תעשו עול במשפט. "Do not render an unfair decision in judgment." This warning is addressed to litigants who are not to try and secure favourable judgment by ruses. If this were to happen it would be considered an עול, an injustice, a perversion of justice. This is the reason the Torah addressed the prohibition in the plural form, i.e. litigants (pl).You may understand this as follows: עול במשפט, the injustice would occur during judgment the judges hand down seeing that the judge is obligated to arrive at his decision on the basis of the arguments presented by the litigants. This is also the reason that this commandment followed the directive not to place obstacles before the "blind." Usually the reason a judge arrives at a faulty decision is that one of the litigants has deceived him.