From the Bible Bibles Commentary: "13:38 The field is the world. It is important to emphasize that the field is the world, not the church. The good seeds mean the sons of the kingdom. It might seem bizarre and incongruous to think of living human beings being planted into the ground. But the point is that these sons of the kingdom were sown in the world. During His years of public ministry, Jesus sowed the world with disciples who were loyal subjects of the kingdom. The tares are the sons of the wicked one. Satan has a counterfeit for every divine reality. He sows the world with those who look like, talk like, and, to some extent, walk like disciples. But they are not genuine followers of the King."
From the James, Faussett, and Brown Commentary: "Then Jesus sent the multitude away, and went into the house: and his disciples came unto him, saying, Declare unto us the parable of the tares of the field, etc. — In the parable of the Sower, “the seed is the word of God†(Luk_8:11). But here that word has been received into the heart, and has converted him that received it into a new creature, a “child of the kingdom,†according to that saying of James (Jam_1:18), “Of His own will begat He us with the word of truth, that we should be a kind of first-fruits of His creatures.†It is worthy of notice that this vast field of the world is here said to be Christ’s own - “His field,†says the parable. (See Psa_2:8)."
From the People's New Testament Commentary: "Matthew 13:36-43
Declare unto us the tares of the field. The parable in Mat_13:24-30 above. By a comparison we may learn: 1. The kingdom is likened to a man sowing good seed in his field. 2. The Sower is the Son of man, who sows by means of his kingdom. 3. The good seed is the word of God as seen in its fruits, Christ's followers. 4. The field is the world. It is Christ's field. All power is given to him in heaven and in earth. His kingdom is rightfully the whole earth, but much of it is held still by the enemy, who has to be conquered. He will prevail finally, and the kingdoms of the earth shall become the kingdom of the Lord and his Christ. 5. The wheat raised from the good seed is the "children of the kingdom," the disciples of Christ converted by his word. 6. The tares are not bad church members, but bad men; those who have been under the influence of the wicked one. 7. The righteous and wicked are to remain in the earth together. The righteous are not to exterminate the wicked. The evil and the good will be mixed until judgment day. 8. Then all shall be gathered at the throne of judgment. The righteous shall "inherit the kingdom." All that are wicked shall be cast out of the kingdom. An eternal separation shall take place."
From The Preacher's Commentary: "The Parable of the Tares Explained
Jesus dismissed the multitude and closed His class for the day. Having entered His house to be away from the crowd, He was alone with the disciples. Fortunately for our understanding, they asked Him to interpret the parable of the wheat and the tares. His answer is clear and concise. The key to its meaning is in the seven terms interpreted in verses Mat_13:37-39 : (1) the sower is the Son of Man, (2) the field is the world, (3) the good seed means the children of the kingdom, (4) the tares are the sons of the wicked one, (5) the enemy is the devil, (6) the harvest is the end of the age, and (7) the reapers are the angels.
The meaning of the parable is that as the Son of Man introduces the kingdom of heaven into the world, the powers of evil will do everything possible to resist the kingdom. Ultimately, the kingdom will succeed. Special attention should be called to His statement that the field is the world, not the church. This parable has often been used to speak against a disciplined church, affirming that Jesus lets the tares remain in the church until the final judgment. Such was the position of Augustine, Luther, Calvin, and others who were defending a church-state, not a believers' church as separate in society. The radical Reformation of the sixteenth century called for an authentic church of believers answering to the mandate of Christ alone. The Anabaptists regarded the Constantinian State Church as a fallen church. The Reformers used this parable against the Anabaptists to justify a people's church where believers and unbelievers (or unconverted) shared together as wheat and tares. But Jesus said, "The field is the world," not the church.
Jesus describes His own role at the end of the age in verse Mat_13:41. The Messiah will be Judge, as foretold by John the Baptist, but Jesus places His action at the end of the age. This judgment is spoken of in Old Testament passages such as Zep_1:2-6. The description, "the furnace of fire," is no doubt lifted from the apocalyptic language of Daniel (Dan_3:6), as is "the righteous will shine forth as the sun in the kingdom of their Father" (Dan_12:3). Note the significant use of the two phrases, "of His kingdom," identifying it as a present reality at work in the world and "the kingdom of their Father," the eternal kingdom. This may best be understood by reading 1Co_15:24, in which Paul shows Christ as completing His kingdom and turning it over to the Father as a fait accompli, a finished work."
From Robertson's Word Pictures: "The field is the world (ho de agros estin ho kosmos). The article with both “field†and “world†in Greek means that subject and predicate are coextensive and so interchangeable. It is extremely important to understand that both the good seed and the darnel (tares) are sown in the world, not in the Kingdom, not in the church. The separation comes at the consummation of the age (sunteleia aiōnos, Mat_13:39), the harvest time. They all grow together in the field (the world)."