36 Then Jesus sent the multitude away and went into the house. And His disciples came to Him, saying, “Explain to us the parable of the tares of the field.”
37 He answered and said to them: “He who sows the good seed is the Son of Man.
38 The field is the world, the good seeds are the sons of the kingdom, but the tares are the sons of the wicked one.
39 The enemy who sowed them is the devil, the harvest is the end of the age, and the reapers are the angels.
40 Therefore as the tares are gathered and burned in the fire, so it will be at the end of this age.
41 The Son of Man will send out His angels, and they will gather out of His kingdom all things that offend, and those who practice lawlessness,
42 and will cast them into the furnace of fire. There will be wailing and gnashing of teeth.
43 Then the righteous will shine forth as the sun in the kingdom of their Father. He who has ears to hear, let him hear!
This is the explanation of the parable that the Lord taught in vs. 24-30.
In the Millennial Kingdom, those who believe in Jesus Christ are represented by the wheat in this parable. Those who don’t believe are the tares.
Sin will be punished severely, so those who don’t believe will behave and look very much like believers, just as tares look like wheat.
But at the end of the age, the unbelievers will be separated and throw into everlasting fire.
Now when the thousand years have expired, Satan will be released from his prison and will go out to deceive the nations which are in the four corners of the earth, Gog and Magog, to gather them together to battle, whose number is as the sand of the sea. They went up on the breadth of the earth and surrounded the camp of the saints and the beloved city. And fire came down from God out of heaven and devoured them. The devil, who deceived them, was cast into the lake of fire and brimstone where the beast and the false prophet are. And they will be tormented day and night forever and ever (Revelation 20:7-10).