What does Matthew 13:38 mean?

At the disciples' request (Matthew 13:36), Jesus is describing a parable He taught to the crowd (Matthew 13:24–30). This parable is called the "parable of the weeds" or the "wheat and the tares." Jesus described a man who sowed good seed into his field. His enemy, though, came in the night and scattered tares, a kind of weed, among the good wheat seeds.

Jesus has said that the man who sowed the field represents Himself, the Son of Man (Matthew 13:37). This is a Messianic title taken from a vision recorded by Daniel (Daniel 7:13–14). Now Christ explains that the field represents the entire world. The good wheat seeds are the "sons of the kingdom" and the weeds are the "sons of the evil one."

By sons of the kingdom, Jesus seems to mean all people who can be described as God's people. These are the ones who will be citizens of His eternal kingdom, the kingdom of heaven. The sons of the evil one are all who, in rejecting Christ, belong to the Devil (John 8:43–47). Jesus allows for only one option or the other. Nobody is described as belong to him- or herself.

Historically, some commentators have taught that "the world" here means "the church" and that those who belong to the Devil will participate in the church alongside those who belong to God as legitimate children of the kingdom. That seems to be quite a stretch, given that Jesus refers to the field as "the world," not "the kingdom." And, that Jesus refers to there being a notable difference between the two (Matthew 13:26–27). The more reasonable explanation is that it is not the church represented by the parable, but the world at large, occupied until the time of judgment both by those who are citizens of God's kingdom and those who are not.