לֹא־תַעֲשׂ֥וּ עָ֙וֶל֙ בַּמִּשְׁפָּ֔ט לֹא־תִשָּׂ֣א פְנֵי־דָ֔ל וְלֹ֥א תֶהְדַּ֖ר פְּנֵ֣י גָד֑וֹל בְּצֶ֖דֶק תִּשְׁפֹּ֥ט עֲמִיתֶֽךָ׃
Não cometereis injustiça no juízo; não levantarás a face do pobre, nem honrarás a face do grande; com justiça julgarás o teu próximo.
Sefer HaMitzvot
That He prohibited us from doing inequity in judgement. That is His, may He be exalted, saying, "You shall not commit injustice in judgement" (Leviticus 19:15). And the content of this negative commandment is that one not go against the rules that the Torah established to make liable for something or to be exempt from it. (See Kedoshim; Mishneh Torah, The Sanhedrin and the Penalties within their Jurisdiction 20.)