It’s an order from God.
And when He had called His twelve disciples to Him, He gave them power over unclean spirits, to cast them out, and to heal all kinds of sickness and all kinds of disease [matthew 10: 1]
And I also say to you that you are Peter, and on this rock I will build My church, and the gates of Hades shall not prevail against it. And I will give you the keys of the kingdom of heaven, and whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed] in heaven. [matthew 16: 18-19]
“If a person sins or touches any unclean thing ... or if a person swears ... 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 sinned ..., so the priest shall make atonement for him concerning his sin” (Levi.5:1-6]