47 Again, the kingdom of heaven is like unto a net, that was cast into the sea, and gathered of every kind: 48 Which, when it was full, they drew to shore, and sat down, and gathered the good into vessels, but cast the bad away. 49 So shall it be at the end of the world: the angels shall come forth, and sever the wicked from among the just, 50 And shall cast them into the furnace of fire: there shall be wailing and gnashing of teeth. (Matthew 13:47-50 KJV)
William Burkitt’s Commentary
The design and scope of this parable also is to set forth the state of the gospel church, which is like a floor, where chaff is mixed with wheat; a field, where tares are mixed with good corn; a net, where bad fishes are involved with the good. As the wheat must not be removed out of the floor before the time of winnowing; nor the tares gathered out of the field before the time of reaping; nor the good fishes break through the net to get from the bad before the time of separation; so must not Christians forsake a church’s communion, because of the present mixture of good and bad in the church. For a mixed communion, in the church, and the good Christians communicating with the bad, do neither defile the ordinances of Christ, nor pollute those that sincerely join in them.