Do you not know that those who minister the holy things eat of the things of the temple, and those who serve at the altar partake of the offerings of the altar? Even so the Lord has commanded that those who preach the gospel should live from the gospel.
In defending his apostleship, Paul makes the case that the Church ministers preaching the gospel have the right to be paid from the tithes and offerings, just as the priests and Levites had eaten of the tithes and offerings in the Old Testament (verses 4 through 12). Just because Paul himself hadn’t exercised this right, he still had the right.
For more about tithing, see our article “Tithing: What Is It? ”