What does Luke 17:9 mean?

Jesus is talking to His disciples about the humility they need as future leaders in the church. They will hold high-ranking positions in the kingdom of God as evangelists and pastors—plowmen and shepherds (Luke 17:7; Ephesians 4:11). But they need to live out of their identities as God's servants. As such, they should always work humbly, without expectation of reward—or even thanks.

The words sound harsh, but the disciples' ambitions make the warning necessary. They ask who is the greatest in the kingdom; Jesus tells them if they don't take the humble character of a child, they won't even get into the kingdom (Matthew 18:1–3). They argue over who is greatest (Luke 9:46). John and James even get their mother involved (Matthew 20:20–21). Jesus responds to all the disciples, saying the Gentiles fight for power, but "it shall not be so among you. But whoever would be great among you must be your servant, and whoever would be first among you must be your slave, even as the Son of Man came not to be served but to serve, and to give his life as a ransom for many" (Matthew 20:26–28).

Jesus lived out this humility. The night before the crucifixion, He took the position of the lowest servant and washed His disciples' feet (John 13:1–5). Paul says Jesus "emptied himself, by taking the form of a servant, being born in the likeness of men" (Philippians 2:7). Jesus—God the Son—served in all humility; the least we can do is follow His example.

The King James Version says, "Doth he thank that servant because he did the things that were commanded him? I trow not." "Trow" is from the Old English treowan which means to trust, believe, or hope. Modern English slang might respond with the phrase, "As if!"