Levítico 19:15 Halajá: Tur, Chafetz Chaim, Mishneh Torah, Murderer and the Preservation & Shulchan Arukh, Choshen Mishpat

And this is the intention of our rabbis z”l, when they say, “All who judge a judgement truthfully, it’s as if he is a partner with God in the creation of the world,” because God created the world to continue and the wicked who steal and commit acts of violence ruin the world through their actions. And similarly we find regarding the generation of the flood that the decree of their judgement was sealed only because of theft, as it is written, (Genesis 6:11) “For the earth is filled with violence,” and it says after this, (Genesis 6:13) “I will destroy them with the earth”. What emerges is that the judge who breaks the high arms of the wicked keeps the world going and completes the will of the Creator, blessed is His name, who created it to keep going, and it is as if they become partners with the Holy One ,Blessed Be He, in the creation. Abraham our forefather didn’t know God, and He called him (Isaiah 41:8) “My beloved” because he walked in the ways of justice and guided his children, as it is written, (Genesis 18:19) “For I have known him, to the end that he may command his children and his household after him, that they may keep the way of God, to do righteousness and justice…” And Moses our teacher a”h, master of all prophets, took advice from Yitro with regards to justice, to establish judges to caution Israel and to command them through justice, and God agreed with this. And Joshua afterwards established a covenant with Israel to serve God, he left his last word as justice, as it is written, (Joshua 24:25) “On that day Joshua made a covenant for the people, and there at Shechem he reaffirmed for them laws and justice.” [This is] because justice is the foundation and the great principle in the service of God, and following [Abraham] have each and every judge judged their generation, and bring them back from their evil ways to service of God to go in the way that Abraham paved to do righteousness and justice, and through this were they [i.e. the Jewish people] were saved from their enemies until Samuel the prophet came, God-faithful, (1 Samuel 7:15-16) “who judged Israel all the days of his life. And he went on a circuit year by year to Bethel, Gilgal, and Mizpah. And he judged Israel in all these places.” And our sages tell us that the path he took one year was not the one he took the next, so that he could turn the hearts of the entire nation toward service of God, and to walk in the way of Abraham our forefather a”h, and he anointed David to be the king of Israel, and he too walked in the ways of God from all that was in front of him, as it is written,(2 Samuel 8:15) “And David did justice and righteousness. (1 Chronicles 11:8) “And Joab restored the rest of the city.” And our sages tell us that in the merit of the justice and righteousness of David, Joab restored the rest of the city, and had his child [Solomon] continue after him, the “Yedid Hashem”, who loved to go in the laws of his father David and would ask from God an understanding, listening heart to judge his people, to understand between good and bad, and it was good in God’s eyes, that which he asked regarding this. And He gave him a wise and understanding heart which has never been before, and no one has been like him since, and all of Israel was afraid of him because they saw that the wisdom of God was in his heart to do justice. And also Jehoshaphat, who took the paths of his father and raised his heart in the ways of God, was strengthened in justice, and he appointed judges in every city, and he said to the judges, “See what you do, for you are not judging for man but for God, and with you shall be justice.” Josiah as well, that Scripture testifies about him, “And no king was like him before, who returned to God with all his heart.” And also the King Messiah, who will be revealed speedily in our days, is praised by Scripture regarding justice, and it is written, (Isaiah 11:4) “And he will judge the destitute with justice, and decide with equity for the meek of the earth…” And according to the greatness of his reward will be the punishment for those who void and pervert it, as it is taught, “Destruction comes to the word based on lack of law and on the perversion of law.” And so did David say, (Psalms 119:121) “I have done justice and righteousness, leave me not to my oppressors.” This implies that without justice, he would have been left in the hands off oppressors. And Jerusalem was only destroyed, and Israel only exiled, because of the neglecting of justice, as it is written, (Isaiah 1:21) “She once was full of justice; righteousness used to dwell in her-- but now murderers.”... And God wants it more than all the sacrifices, as it is written, “Doing righteousness and justice is choicier to God than the zevach offerings.” It does not says “than sin and burnt offerings,” but rather “than zevach offerings.”

But this din is subject to various qualifications, as I shall explain. For if he [the object of the lashon hara] were a "mediocre" person, a plain man of Israel, who generally guarded himself against sin, and "stumbled" in this sin only occasionally, and it is possible to assume that he committed this sin unintentionally, or that he did not know this thing to be forbidden, or that he thought the ruling to be a stringent one [chumra], or conducing to a good trait in general, which saintly men are circumspect in — then, even if he saw him transgress this several times, he should certainly be given the benefit of the doubt, and it is forbidden to expose him, so that he not be an object of shame before his people, and so that he not be shamed even in his own eyes. And it is forbidden to hate him for this, for he must be judged in the scales of merit, this being a positive commandment of the Torah, according to many poskim, viz. (Vayikra 19:15): "In [the scales of] righteousness shall you judge your friend."

And if he suffered a business loss and did not know its cause, as when he held a lease from a landowner and was dismissed by him, and he did not know whether someone had slandered him or whether the landowner had dismissed him at his own initiative — it is forbidden to suspect a Jew (unless there are "indications" pointing to him [as will be explained below], in which instance he is permitted to believe the rechiluth in his heart; but he is not permitted to cause him [the suspect] any loss thereby [as will be explained below].) For it is forbidden to categorize a Jew as an "evildoer." And concerning this it is said (Vayikra 19:15): "In [the scales of] righteousness shall you judge your fellow."