Thou shalt not go up and down. The principle of the second clause is the same as that of the foregoing verse, for it is added to a general precept, whereby detraction is condemned: and much more ought we to be deterred from it, whilst we acknowledge that our tongue is thus armed cruelly to shed innocent blood. Some suppose that the word rkyl, racil, is metaphorically taken from merchants, because the tale-bearer or whisperer [1] is no less busy in hunting for false reports, which he may afterwards circulate, than the merchant is diligently bent on buying and selling. Others think that there is a change of the letter g into k; and that thus the word is derived from the feet; because calumniators are always wandering about to hunt for grounds of detraction; and therefore is always joined with a verb which signifies to walk. I do not think, however, that it is always used in the same sense; for when Ezekiel reproves the Israelites, because there were always men called rkyl, racil, among them, to shed blood, [2] I understand men of fraud, or fraudulent persons, who plot against the good to procure their destruction. (Ezekiel 22:9.) Some also translate it spies. Meanwhile, I doubt not, but that Moses, in this passage, designates those vagabonds, who too eagerly run about hither and thither, and in their malignant inquisitiveness penetrate into everybody's secrets, to bring quiet people into trouble. In short, we are taught that they are accounted false witnesses before God, whosoever by the virulence of their tongue bring their brethren into danger and inconvenience.

Footnotes

1 - "Delator aut susurro." -- Lat. "The original properly signifies a trader, a pedlar, and is here applied to one who travels up and down dealing in slanders and detractions, as a merchant does in wares, possessing himself of the secrets of individuals and families, and then blazing them abroad, usually with a false colouring as to motives and a distortion of facts." -- Bush. "Some explain rkyl as if rgyl, (the g being changed into k,) from rgl, to run about, to explore." -- Fagius, from the Hebrew Commentators, in Poole's Synopsis. "Non reperimus in S. Scriptura dictionem rkylvt, quae non sit scripta lingua hlykh, i e., ambulationis." -- Sal. Jarchi in loco. See C. on Jeremiah 9:4, Cal. Soc. edit., [18]vol. 1, p. 464

2 - "In thee are men that carry tales (margin, men of slanders) to shed blood." -- A.V.

Stand against the blood of thy neighbor - Either, to put his life in danger by standing up as his accuser (compare Matthew 26:60); or, to stand by idly when thy neighbor's life is in danger. Whichever interpretation we adopt, the clause prohibits that which might interfere with the course of justice.

Thou shalt not go up and down as a tale-bearer - רכיל rachil signifies a trader, a peddler, and is here applied to the person who travels about dealing in scandal and calumny, getting the secrets of every person and family, and retailing them wherever he goes. A more despicable character exists not: such a person is a pest to society, and should be exiled from the habitations of men.
Neither shalt thou stand against the blood, etc. - Thou shalt not be as a false witness, because by such testimony the blood - the life of an innocent man may be endangered.

Thou shalt not (e) go up and down [as] a talebearer among thy people: neither shalt thou (f) stand against the blood of thy neighbour: I [am] the LORD.
(e) As a slanderer, backbiter, or quarrel picker.
(f) By consenting to his death, or conspiring with the wicked.

Thou shall not go up and down as a talebearer among thy people,.... The word used signifies a merchant, and particularly one that deals in drugs and spices, and especially a peddler in those things, that goes about from place to place to sell them; and such having an opportunity and making use of it to carry stories of others, and report them to their disadvantage, hence it came to be used for one that carries tales from house to house, in order to curry favour for himself, and to the injury of others; and such a man is a detestable person, and ought not to be encouraged, see 1-Timothy 5:13,
neither shall thou stand against the blood of thy neighbour; either by bearing a false testimony, whereby his blood is in danger of being shed when innocent; or by being silent, and not hearing a testimony for him, whereby the shedding of his innocent blood might have been prevented; either way may be interpreted standing against it: the Jewish writers think, that a man by this law, is bound to do all he can to preserve the life of his neighbour, when it is by any means in danger, by drowning, or by thieves and wild beasts, so Jarchi:
I am the Lord; the just and righteous One, who will resent and punish for all unjust proceedings in courts of judicature, secret tale bearing, doing any injury to another, or not preventing it when in the power of his hands.

They were not to go about as calumniators among their countrymen, to bring their neighbour to destruction (Ezekiel 22:9); nor to set themselves against the blood of a neighbour, i.e., to seek his life. רכיל does not mean calumny, but, according to its formation, a calumniator (Ewald, 149e).

Stand against the blood - In judgment as a false accuser or false witness, for accusers and witnesses use to stand, whilst the judges sit in courts of judicature.