Church is derived from the Old Testament where the people of Israel were the assembly of the LORD (for example, Deuteronomy 23:2, Deuteronomy 23:8; 1 Chronicles 28:8) or the assembly of Israel (for example, Leviticus 16:17; Deuteronomy 31:30; 1 Kings 8:14, 1 Kings 8:22). When Paul says that he persecuted the church of God, he is primarily thinking of the church in Jerusalem (Acts 8:3) though his persecution was not limited to that church (Acts 26:10).1 Also, when he talks about the church of God,
he thereby asserts that the Christian church is the true assembly of God’s people,2 the fulfilment of what God intended with Israel.3 Opposition to the church is thus opposition to God.4
13 For you have heard of my former life in Judaism, how I persecuted the church of God violently and tried to destroy it.