The New Testament tells us quite clearly that Paul did not always receive financial support from the churches he planted or ministered to. For example, 1 Corinthians 9:12 tells us that the Apostle took no wages from the church in Corinth, and 1 Thessalonians 2:9 indicates that Paul received no funds to support himself from the church at Thessalonica either. This did not mean he had no right to such support. Paul actually claims such a right in 1 Corinthians 9:3–12, and at times he did make use of financial gifts given to pay for his physical needs (Phil. 4:14–20).
Paul did not refuse financial assistance because he and the other Apostles had no legitimate claim to it; rather, he would sometimes surrender this right to support in order to remove any obstacles to the gospel (1 Cor. 9:12). Before going into more detail on his freedom to surrender his rights, however, Paul devotes a final few verses to demonstrating that those who labor in gospel ministry do no wrong in accepting payment for their work. He even says that it should be the normative practice of the church to pay its teachers and preachers.
To do this, the Apostle points out that under the old covenant, the priests and Levites received their food from the sacrifices (v. 13). Here Paul refers to texts such as Numbers 18, which instructed the priests and Levites to take a portion of the tithes and offerings and sacrifices brought to the temple and tabernacle to meet their needs. Unlike the other tribes of Israel, the tribe of Levi had no territory of its own from which to make a living but only cities located in the territories of the other tribes (Lev. 25:32; Josh. 14:4). That was insufficient in that agrarian society to meet all the needs of that tribe, so the Levites and priests, who belonged to Levi, were supported also by the offerings, tithes, and gifts of the Israelites. Under the old covenant, they did the gospel work, as it were, of teaching the people and leading in worship, and they were paid by the contributions of the other tribes of Israel.
In the same way, Paul says, “Those who proclaim the gospel should get their living by the gospel” (1 Cor. 9:14). New covenant pastors and teachers, like the priests of old, are tasked with the gospel work of teaching and leading in worship. Thus, they have a right to be paid by the gifts and offerings of new covenant believers. Indeed, this is how the Lord says things should be (v. 14).