Jesus had sent the multitude away, and was now in a house in Capernaum. This may have been Peter's home.
And His disciples came to Him, saying, "Explain to us the parable of the tares of the field."
Sower, field, and seed
He answered and said to them: "He who sows the good seed is the Son of Man. The field is the world, the good seeds are the sons of the kingdom, but the tares are the sons of the wicked one.
Enemy, harvest, and reapers
The enemy who sowed them is the devil, the harvest is the end of the age, and the reapers are the angels.
Therefore as the tares are gathered and burned in the fire, so it will be at the end of this age.
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, and will cast them into the furnace of fire. There will be wailing and gnashing of teeth.
Then the righteous will shine forth as the sun in the kingdom of their Father. He who has ears to hear, let him hear!"
Jesus gave a concise explanation. Note that the field is the world, not the church. So this parable does not prohibit church discipline.
Angels play an interesting role in this parable. They separate the good from the bad, and cast the evil ones into hell. Angels also play an important role in the Parable of the Net.