This parable exposes the problem of evil intermingled with good within congregations, just as the same mix confronts nations, communities, and homes. No matter how society tries to legislate or separate out lawbreakers from the rest of society, the seeds of sin and crime find a place to grow. God's church is similarly affected by Satan's constant attacks. The genuine and the counterfeit wheat are always together in the church.
The servants' perplexity about the sowing of the tares shows that the presence of sin is often a mystery to people (II Thessalonians 2:7-10). God cannot be blamed for them because He does not sow evil—Satan does (James 1:13). By this parable, Jesus prophesies that the church of God on earth would be imperfect. The spiritual church has members with the Holy Spirit who are dedicated and loyal, yet have personal defects. It also has within it unconverted people who may recognize the truth but are there only to enjoy association with God's people. Jesus' intent is to enlighten and warn the saints of this fact, not to expose the tares at this time (Acts 20:29-32). God will root out the bad seed when the good seed has matured.
"The good seed," "the wheat," and "the sons of the kingdom" refer to baptized members of God's church in whom the Holy Spirit dwells—the saints, the elect, the righteous (Matthew 13:43). In the previous parable, the seed represents "the word of the kingdom" (verse 19), but here, the good seed is the product of that word received, understood, and obeyed. The Son of Man, as the Sower or Owner, sows only good seed, those who are righteous due to walking worthy of God—living His way of life, and becoming the "children of the kingdom" (I John 2:6; II John 6; I Thessalonians 2:10-15).
It is God's will that Jesus Christ the Redeemer sow His redeemed ones in this world of sin and misery for the purpose of training and testing them to become true witnesses for Him in preparation for the Kingdom. Therefore, He has placed Christians where He wants them. Jesus tells Peter in Luke 22:31 that he was wheat, and as such, he was to be sifted by Satan. All of God's saints should heed this warning to watch and pray that the field of our heart not be sown with tares by the enemy. God has bought us with a price and given us His Spirit, making us new creations in Him and heirs of His Family and eternal life. He expects us to bear fruit in our corner of the field of this world in which He has sowed us.