Under the Law Atonement: Offered For: Persons Swearing Rashly
Source: TTT
Leviticus 5:4, 6
Or if someone swears thoughtlessly with his lips to do anything good or evil—in whatever matter a man may rashly pronounce an oath—even if he is unaware of it, when he realizes it, he is guilty in the matter. / and he must bring his guilt offering to the LORD for the sin he has committed: a female lamb or goat from the flock as a sin offering. And the priest will make atonement for him concerning his sin.