Albert Barnes Commentary Matthew 13:30

"Let both grow together until the harvest: and in the time of the harvest I will say to the reapers, Gather up first the tares, and bind them in bundles to burn them; but gather the wheat into my barn." — Matthew 13:30 (ASV)

Let both grow together. They would not spoil the true wheat; and in time of harvest it would be easy to separate them. Our Savior teaches us here:

1. That hypocrites and deceived persons must be expected in the church.
2. That this is the work of the enemy of man. They are not the work of Christianity, any more than traitors are of patriotism, or counterfeiters are of the proper effect of legislating about money. They belong to the world; and hypocrisy is only one form of sin. The Christian religion never made a hypocrite; nor is there a hypocrite on the face of the earth whose principles and practice it does not condemn.
3. That all hope of removing them entirely would be vain.
4. That an attempt to remove them altogether would injure real Christianity, by causing excitements, discord, and hard feelings even among Christians.
5. That He will Himself separate them at the proper time.

There is no doubt that it is the duty of the church to attempt to keep itself pure, and to cut off gross and manifest offenders (1 Corinthians 5:4–5). He refers to those who may be suspected of hypocrisy, but against whom it cannot be proved; to those who so successfully imitate Christians as to make it difficult or impossible for humans to distinguish them.