This verse appears to refer to the saying of Jesus that is recorded in Matt 10.10 and Luke 10.7, and is quoted in 1 Tim 5.18 alongside an Old Testament text (see also Gal 6.6). The sentence does not mean that Jesus gave an order directly to teachers of the gospel, but that he gave instructions concerning how these teachers should support themselves. The Greek has simply “live,” but both Revised Standard Version and Good News Bible correctly expand this to get their living. The meaning is determined both by the immediate context and by “get their food” in verse 13. The final phrase should get their living by the gospel may also be rendered as “should support themselves from preaching the Good News.”

Quoted with permission from Ellingworth, Paul and Hatton, Howard A. A Handbook on Paul’s First Letter to the Corinthians, 2nd edition. (UBS Handbook Series). New York: UBS, 1985/1994. For this and other handbooks for translators see here .