A Parable from St. John, modified in the light of my rural experiences...

There was a man of the city who inherited an empty field from a distant relative, and resolved to be a good farmer. He bought the best seed he could from the seed-sellers, and had his servants sow it in his field, and manured and watered his field as he found it written that it should be done. But the wind scattered other seeds into his field, and others came on the feet of birds, or were lying sleeping in the soil for such watering and manuring as the man gave the field. So when the wheat sprouted and formed heads, many weeds also appeared.
The owner’s servants came to him and said, ‘Master, did you not sow the best seed in your field? Where then did the weeds come from?’
‘An enemy did this,’ he replied, thinking that some enemy of his had come in the night, and sowed bad seed among his good seed, for all his knowledge of farming had come out of books, and he did not know how the weeds had come into his field.
The servants asked him, ‘Do you want us to go and pull them up?’
‘No’, he answered, ‘ You are ignorant of farming, and while you are pulling the weeds, you may root up my good plants along with them. Let both grow together until the harvest. At that time I will tell the harvesters: First collect the weeds and tie them in bundles to be burned, then gather the wheat and bring it into my storehouse.’
But when the time of the harvest came, the field was only a wilderness of thorns and poisonous weeds. There was not one good plant in a thousand in the field, for wherever the good plants had grown they had been choked by the weeds. And the owner said to himself, ‘A thousand times more difficult it is now, to find the one good plant among so many bad, then it would have been to dig out the bad plants from the good at the beginning of the season. Now I must harvest all that grows in my field, and have it burned. For fear of losing some of my crop I have lost it all, and thinking myself a wise farmer I have proved myself foolish. In the next season I will not be foolish, but I will send out my servants to weed my field. True it is what the prophets say: whoever wishes to save what he has will lose it, while he who is willing to lose what he has will be rewarded many times over.’