"Parable of the Weeds"

Another parable set he before them, saying, The kingdom of heaven is likened unto a man that sowed good seed in his field:
but while men slept, his enemy came and sowed tares also among the wheat, and went away.
But when the blade sprang up and brought forth fruit, then appeared the tares also.
And the servants of the householder came and said unto him, Sir, didst thou not sow good seed in thy field? whence then hath it tares?
And he said unto them, An enemy hath done this. And the servants say unto him, Wilt thou then that we go and gather them up?
But he saith, Nay; lest haply while ye gather up the tares, ye root up the wheat with them.
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 13:24-30