Leviticus 5

Leviticus 5 provides a backdrop to our judicial witness process.

Per Wikipedia...

United States

Oath:

Do you solemnly swear or affirm that you will tell the truth, the whole truth, and nothing but the truth, so help you God?

Note: In some cases "so help you God" may be replaced with "under pains and penalties of perjury".

Oath (California):

You do solemnly state that the testimony you may give in the cause now pending before this court shall be the truth, the whole truth, and nothing but the truth, so help you God.

Lev 5:1    And if a soul sin, and hear the voice of swearing, and is a witness, whether he hath seen or known of it; if he do not utter it, then he shall bear his iniquity.

Leviticus 5:1Gill

And if a soul sin,.... The soul is put for the person, and is particularly mentioned, as Ben Melech says, because possessed of will and desire:

and hear the voice of swearing; or cursing, or adjuration; not of profane swearing, and taking the name of God in vain, but either of false swearing, or perjury, as when a man hears another swear to a thing which he knows is false; or else of adjuration, either the voice of a magistrate or of a neighbour adjuring another, calling upon him with an oath to bear testimony in such a case; this is what the Jews (r) call the oath of testimony or witness, and which they say (s) is binding in whatsoever language it is heard:

and is a witness; is able to bear witness to the thing he is adjured about:

whether he hath seen or known of it; what he has seen with his eyes, or knows by any means: of such a case, the Jews observe (t), that there may be seeing without knowing, or knowing without seeing, and in either case a man ought to bear witness:

if he do not utter it; tell the truth, declare what he has seen or known:

then he shall bear his iniquity; he shall be charged with sin, and be obliged to acknowledge his offence, and bring a trespass offering for it: it is said (u), that the witnesses are not guilty of the oath of the testimony, but in these ten cases; if they are required; if the testimony is concerning goods; if the goods are movable; if he that requires binds himself to pay for their testimony only, in case they bear witness; if they refuse after required; if they refuse in the sanhedrim; if the adjuration or oath is made there by the name of God, or his titles; if knowledge of the testimony goes before the oath; if he particularizes his witnesses in the time of the oath, or at the time of the requirement; and if the oath is in a language they understood.

(r) Misn. Sotah, c. 7. 1. (s) Maimon. & Bartenora in ib. T. Bab. Sotah, fol. 33. 1. (t) T. Bab. Shebuot, fol. 33. 2. & 34. 1. (u) Maimon. Hilchot, Shebuot, c. 9. sect. 3.