Leviticus 5:4-6

CLV(i) 4 or when a soul swears, talking rashly with the lips to do evil or to do good as to anything of which a human talks rashly in an oath, even if it is obscured from him, when he himself realizes it, then he is guilty as to any one of these. 5 It will come to be when he realizes his guilt as to any one of these instances then he will confess in what way he has sinned; 6 and he will bring as his guilt offering to Yahweh for his sin with which he has sinned, a female from the flock, a sheep or a hairy female of the goats, as a sin offering. Then the priest will make a propitiatory shelter over him for his sin with which he has sinned, and it will be pardoned him.