Leviticus 5 begins with several ways in which an Israelite might sin, such as touching an unclean thing, touching human uncleanness, foolish oaths, and in some of those cases, the person was guilty, whether he realized it or not, and in other cases, he became guilty after learning of his actions (Leviticus 5.1–4). Once a person realized how he had trespassed, going where he should not go according to God’s law, he would do the following,

“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” (Leviticus 5.5–6).

If the guilty Israelite did what the Lord wanted, the priest would make atonement for that guilty person, freeing him from his sin. That person had to confess the sin, but also had to take a certain animal, and bring it as a sin offering, showing the serious nature of sin.

If that does not convince you that sin is serious, consider the great sacrifice that God made that we might have atonement, when He offered His blessed Son on a cruel Roman cross for our sins.