Jesus told them another parable: “The kingdom of heaven is like a man who sowed good seed in his field. But while everyone was sleeping, his enemy came and sowed weeds among the wheat, and went away. When the wheat sprouted and formed heads, then the weeds also appeared.
“The owner’s servants came to him and said, ‘Sir, didn’t you sow good seed in your field? Where then did the weeds come from?’
“‘An enemy did this,’ he replied.
“The servants asked him, ‘Do you want us to go and pull them up?’
“‘No,’ he answered, ‘because while you are pulling the weeds, you may uproot the wheat with them. Let both grow together until the harvest. At that time I will tell the harvesters: First collect the weeds and tie them in bundles to be burned; then gather the wheat and bring it into my barn.’”
The last thing anybody wants when they are planting seeds is to discover later that their seeds included the seeds of weeds, so seed providers are very careful to ensure that their seed packages are clear of such an infestation. In this parable, a farmer had good wheat seeds, free of weeds, but his enemy came into the field under cover of night and infested the man’s fields with weeds; nice guy.
Jesus began the story by saying that the kingdom of heaven is like that. I’m sure I don’t really need to explain this to anybody, but obviously, the Gospel is represented by the seeds, the enemy is Satan, and the weed seeds are the notions, cares and philosophies of this world. As the Gospel message begins to grow inside a person, the weeds of the enemy grow and seek to choke out the pure message of hope. In the end, when the time has come for harvest, the Harvester will pull out the weeds so they can be burned, and the wheat will be harvested.
You might want to take note of the apocalyptic implications of this, for when Jesus returns, those weeds in the harvesting fields will be separated from the harvest and burned.
We might also note, in light of the previous passage, that the parables Jesus is using to explain the Kingdom are really not very hard to follow, unless of course, you just don’t want to follow them.