But we know that the law is good, if a man uses it lawfully,

 (i) He may be thinking of the Jewish practice of excommunication. According to synagogue practice, if a man was an evil-doer he was first publicly rebuked. If that was ineffective, he was banished from the synagogue for a period of thirty days. If he was still stubbornly unrepentant, he was put under the ban, which made him a person accursed, debarred from the society of men and the fellowship of God. In such a case a man might well be said to be handed over to Satan. 