What does Matthew 19:30 mean?

The disciples have learned of an astonishing eternal future that waits for them. They have also heard about great rewards for anyone who fully commits to following Christ (Matthew 19:28–29). Jesus concludes that promise with a puzzling statement intended to set up the parable which begins the next chapter.

Jesus says that many who are first will be last, and the last first. The parable will explain the idea more fully, but in general it seems to be this: Those who have lost the most on earth to follow Jesus in this life will receive eternal rewards alongside those who sacrificed much less by comparison. Not all the rewards will be the same, necessarily, but some who were wealthy on earth will be the last in the kingdom and some who were last on the earth will be first in the kingdom. In all cases, God will keep His promises to all, and none will have legitimate reasons to describe God as unfair. Nor will anyone have reason to think their status in life directly reflects their status in eternity.