an oath of the Lord

Leviticus 5:1
If someone sins by failing to testify when he hears a public charge about something he has witnessed, whether he has seen it or learned of it, he shall bear the iniquity.

Leviticus 6:3
or finds lost property and lies about it and swears falsely, or if he commits any such sin that a man might commit--

1 Kings 2:42, 43
the king summoned Shimei and said to him, "Did I not make you swear by the LORD and warn you, 'On the day you leave and go elsewhere, know for sure that you will die'? And you told me, 'The sentence is fair; I will comply.' . . .

Proverbs 30:9
Otherwise, I may have too much and deny You, saying, "Who is the LORD?" Or I may become poor and steal, profaning the name of my God.

Hebrews 6:16
Men swear by someone greater than themselves, and their oath serves as a confirmation to end all argument.

that he hath not

Exodus 22:8
If the thief is not found, the owner of the house must appear before the judges to determine whether he has taken his neighbor's property.

Exodus 23:1
You shall not spread a false report. Do not join the wicked by being a malicious witness.