Commentaire sur Amos 2:6

for selling an innocent man for money—The judges would sell the one who was innocent according to the law, with money; i.e, with the bribes they would receive from his opponent.

and a poor man in order to lock [the fields] Heb. נַעֲלָיִם. Jonathan renders in two places [here and below 8:6]: in order to inherit. And I say that this is its explanation. They pervert the judgment of the poor man so that he will be compelled to sell his field that he had between the fields of the judges, and this one seeks an opportunity and takes it for a cheap price in order to fence in and lock all his fields together, and it should not intervene between them.

Thus said the LORD...Because they have sold for silver Those whose cause was just: Even though Israel had transgressed the three worse sins (those being idolatry, sexual immorality, and bloodshed)-- for those, they did not receive the decree of destruction and exile at the hands of the king of Assyria-- rather, because of the חמס/violence, which is the fourth sin (mentioned in Amos), and on the basis of that sin they were punished for all their sins that they did. And this is the same as the generation of the flood. Even though they were guilty of several sins, they were not punished until they were guilty of חמס, as it says "כִּֽי־מָלְאָ֥ה הָאָ֛רֶץ חָמָ֖ס מִפְּנֵיהֶ֑ם for the earth is filled with lawlessness because of them" (Gen 6:13). And even more so because the חמס came at the hands of the judges, who were responsible for upholding justice, but they decided their rulings based on taking bribes, which is what עַל־מִכְרָ֤ם" בַּכֶּ֙סֶף֙ צַדִּ֔יק/Because they have sold for silver

those whose cause was just" means, and the explanation of "צַדִּ֔יק" in that verse is "one whose cause was just."