Leviticus 19:16

You shall not go about as a talebearer: I say that, since all those who start quarrels and speak lashon hara go into homes to seek what evil they can see, or what evil things to tell in the marketplace, they are called הולכי רכיל, [the same as] הולכי רגילה, - “those who go about spying”. A proof for my words is that we do not find the term רכילות without being expressed as הליכה , “going”; as לֹא תֵלֵךְ רָכִיל, “You shall not go about as a talebearer,” and, “going tale bearing (הוֹלְכֵי רָכִיל) (Jer. 6:28); [like] copper and iron.” (TBC)

Don't stand idly by the blood of your neighbor: To see his death and you are able to save him, such as one drowning in a river, or an animal or bandits are advancing on him

I am Hashem: Dependable to repay reward, and dependable to exact payment.

Thou shalt not go after the slanderous tongue, which is cruel as a sword that killeth with its two edges in uttering false accusations to afflict thy people. Thou shalt not hinder the acquittal of thy neighbour in witnessing against him in the judgment: I am the Lord.

a talebearer from the word “your merchandise” [Ezekiel 28:16] and also “…with all powders of the merchant” [Song of Songs 3:6]. Here the word denotes a gossiper. Just as a merchant transmits things, buying them here and selling them there, so also does a gossiper transmit things, revealing to one what he heard from another.

Do not stand idle when your fellowman is in danger [literally: Do not stand upon your fellowman’s blood] One must not become involved with men who shed blood. It is well known that many people have been murdered, many people have been killed, because of slander. Doeg the Edomite is a prime example [I Samuel 22:9–19].

I am God Who sees all that you do in private.

THOU SHALT NOT ‘THEILEICH RACHIL’ (GO UP AND DOWN AS A TALEBEARER) AMONG THY PEOPLE. “I say that because all those who sow discord [among brethren] and speak slander go into their friends’ houses in order to spy out what evil they can see or hear, so that they may tell it in the street — therefore they are called holchei rachil or holchei regilah (‘those who go about spying’) etc. And so did Onkelos translate [the verse before us]: lo theichul kurtzin [literally: ‘thou shalt not eat kurtzin’, which has the same meaning as], ‘va’achalu kartzeihon’ (and they brought accusation against) the Jews; ‘achlu kurtza (they slandered him) to the king.’ It appears to me that it was their custom to eat something in the house of him who accepted their slanderous words, this being a sort of final confirmation that the slanderer’s words are well-founded, and that he would stand by them. It was this snack that was called ‘the eating of kurtzin,’ [the word being associated with] the [Hebrew] expression, ‘koreitz’ (he that winketh) with his eyes, for such is the manner of all who go about slandering, to wink with their eyes, and to insinuate slanderous matters in order that [others who happen to] hear them should not understand them.” All this is the language of the Rabbi [Rashi].
But his explanation of this rendition of Onkelos has neither rhyme nor reason. For one who listens to a slanderer does not swear to him that he will believe his words, and [therefore the slanderer] need not give him a sign or token [to believe him]! Even when one slanders a servant to his master,. Ramban’s intention is therefore as follows: Even in slandering a slave, where the slanderer runs the risk of incurring his curse, the master nonetheless gives the slanderer no assurance that he will listen to him, and so what sense is there to this “eating” on the part of the slanderer which Rashi mentioned? the master does not assure him that he will listen to him, and so what sense is there to this “eating” [by the slanderer, as Rashi mentioned]? And Nebuchadnezzar did what he decided to do on the basis of his own decision about the righteous ones,, and it is told that certain slanderers came and informed Nebuchadnezzar that Hananiah, Mishael, and Azariah, were not bowing to his image of gold. As a result he called them and asked them if it was true. When they told him that they had no intention ever of bowing to …

לא תלך רכיל, do not go around bearing tales (untrue ones). We find a similar verse in Daniel 3,8 “Chaldeans slandered the Jews.” Samuel II 22,14 ירעם משמים, G’d thundered forth from heaven, is also translated as אכלי, by Yonathan ben Uzziel, being the equivalent of the Hebrew רכיל in our verse, i.e. raising one’s voice.

לא תעמוד על דם רעך, do not stand by idly but go to his assistance.