A.T. Robertson Commentary 1 Corinthians 9:14

"Even so did the Lord ordain that they that proclaim the gospel should live of the gospel." — 1 Corinthians 9:14 (ASV)

Even so did the Lord ordain (ουτως κα ο Κυριος διεταξεν). Just as God gave orders about the priests in the temple, so did the Lord Jesus give orders for those who preach the gospel to live out of the gospel (εκ του ευαγγελιου ζηιν). Evidently Paul was familiar with the words of Jesus in Mt 10:10; Luke 10:7f. either in oral or written form. He has made his argument for the minister's salary complete for all time.