Rashi on Leviticus 19:15/רש"י על ויקרא י״ט:ט״ו

1לא 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.

2לא תשא פני דל THOU SHALT NOT RESPECT THE PERSON OF THE INDIGENT — i. e. thou shalt not say, "This is a poor man, and the rich man has in any case the duty of supporting him; I will find in favor of him (the poor man) and he will consequently obtain some support in a respectable fashion (Sifra, Kedoshim, Chapter 4 2).

3ולא תהדר פני גדול NOR HONOR THE PERSON OF THE MIGHTY — thou shalt not say, “This is a rich man, or, this man is of noble descent (lit., the son of great people) how can I possibly put him to shame and be witness to his shame? There is punishment for such a thing!” It is for this reason that Scripture states, "thou shalt not honor the person of the mighty” (Sifra, Kedoshim, Chapter 4 3).

4בצדק תשפט עמיתך IN RIGHTEOUSNESS SHALT THOU JUDGE THY COMPANION — Take this as the words imply (i.e. take the word צדק as what it usually implies: strict right). Another explanation is: Judge thy fellow man with an inclination in his favour (Sifra, Kedoshim, Chapter 4 4; Shevuot 30a).