Leviticus 5:2-6

‘Or if a person touches any unclean thing, whether it is the carcass of an unclean beast, or the carcass of unclean livestock, or the carcass of unclean creeping things, and he is unaware of it, he also shall be unclean and guilty. Or if he touches human uncleanness—whatever uncleanness with which a man may be defiled, and he is unaware of it—when he realizes it, then he shall be guilty. ‘Or if a person swears, speaking thoughtlessly with his lips to do evil or to do good, whatever it is that a man may pronounce by an oath, and he is unaware of it—when he realizes it, then he shall be guilty in any of these matters. ‘And it shall be, when he is guilty in any of these matters, that he shall confess that he has sinned in that thing; and he shall bring his trespass offering to the LORD for his sin which he has committed, a female from the flock, a lamb or a kid of the goats as a sin offering. So the priest shall make atonement for him concerning his sin.