To accept the person of the wicked - We must not, in judicial cases, pay any attention to a man's riches, influence, friends, offices, etc., but judge the case according to its own merits. But when the wicked rich man opposes and oppresses the poor righteous, then all those things should be utterly forgotten.

[It is] not good to (e) accept the person of the wicked, to overthrow the righteous in judgment.
(e) That is, to favour him and support him.

It is not good to accept the person of the wicked,.... For a judge to have respect to a wicked man in a cause before him, and to favour him, because he is a rich man, or a relation, or he has received some kindness from him; none of these things should have any influence upon him
to overthrow the righteous in judgment: though he may be a poor man and a stranger, and to whom the judge is under no private and personal obligation; yet justice ought to be done without any respect to persons; to do otherwise is not only not good, but very bad, very sinful and criminal; it is contrary to law and justice; it is doing injury to men, and is repugnant to the will of God, and offensive to him, Leviticus 19:15.

The merits of a cause must be looked to, not the person.

accept the person--(Compare Psalm 82:2). "It is not good" is to be supplied before "to overthrow."

5 To favour the person of the godless is not good,
And to oppress the righteous in judgment.
As Proverbs 18:4 has one subject, so Proverbs 18:5 has one predicate. The form is the same as Proverbs 17:26. שׂאת פּני (cf. Proverbs 24:23), προσωποληψία, acceptio personae, is this, that one accepts the פני, i.e. the personal appearance of any one (πρόσωπον λαμβάνει), i.e., regards it as acceptable, respectable, agreeable, which is a thing in itself not wrong; but in a judge who ought to determine according to the facts of the case and the law, it becomes sinful partiality. הטּות, in a forensic sense, with the accus. of the person, may be regarded in a twofold way: either as a turning aside, מדּין, Isaiah 10:2, from following and attaining unto the right, or as an oppression, for the phrase הטּה משׁפּט [to pervert justice] (cf. Proverbs 17:23) is transferred to the person who experiences the oppression = perversion of the law; and this idea perhaps always underlies the expression, wherever, as e.g., Malachi 3:5, no addition brings with it the other. Under Proverbs 17:15 is a fuller explanation of לא־טוב.