Leviticus 5:3-5

Amplified Bible

³ Or if he touches human uncleanness—whatever kind it may be—and he becomes unclean, but he is unaware of it, when he recognizes it, he will be guilty. ⁴ Or if anyone swears [an oath] thoughtlessly or impulsively ^[a]aloud that he will do either evil or good, in whatever manner a person may speak thoughtlessly or impulsively with an oath, but he is unaware of it, when he recognizes it, he will be guilty in one of these.^{(A) 5} So it shall be when a person is guilty in one of these, that he shall confess the sin he has committed.