What does Matthew 13:39 mean?

Jesus is explaining to His disciples the parable He told to the crowd about the wheat and the weeds (Matthew 13:24–30). He has said the one who sows good seed into a field represents Himself, the Son of Man (Matthew 13:37). The field itself is the whole world, and the good wheat seeds being sown are the sons of the kingdom, those who will become the citizens of God's eternal kingdom. Jesus identified the weeds as the sons of the evil one (Matthew 13:38), leaving only two eternal categories for humanity: those who belong to God and those who belong to Satan.

Now He adds that the Devil is the one who planted the weeds among the good wheat seeds. It is because of the enemy that those who belong to Satan exist alongside those who belong to God in the world. However, the harvest will come eventually. In the parable itself, the farmer waits to uproot the weeds until the harvest, at which time they will be sorted out and burned (Matthew 13:30). Jesus describes that harvest as the end of the age, the prophesied time of God's judgment, sometimes called the "day of the Lord." Jesus now says that those who will harvest the field, the reapers, will be His angels. Jesus describes their grim work in the following verses.