What does Matthew 20:1 mean?

Jesus has assured the disciples that they will be richly rewarded for all they have lost for His name's sake, in addition to inheriting eternal life. He concluded though by telling them that many who are first will be last, and the last first (Matthew 19:27–30).

Now Jesus uses a parable to illustrate what that means. A parable usually takes the form of a very brief story, as it does in this passage. Jesus often begins His parables by saying "the kingdom of heaven is like" the story that follows. His parables provide snapshots and impressions of the way His kingdom works for those who will spend eternity there. In this case, Jesus is describing the kingdom in terms of the reward to be given to those who work on His behalf.

He begins by describing the master of a house. This master owns a vineyard, and it is apparently harvest time. It was common to hire temporary workers during the harvest when the work became more than the full-time servants could handle on their own. Those available for temporary work would gather in the marketplace in hopes of being hired for the day.