Because you say, "I am rich, have become wealthy, and have need of nothing"—and do not know that you are wretched, miserable, poor, blind, and naked.... —Revelation 3:17
The wilderness encroaches on the fruitful field, and unless there is constant fighting off of this encroachment there will be little or no harvest.
I think it is exactly the same with the church, for as one of the old saints said, "Never think for a minute that there will be a time when you will not be tempted. He is tempted the most effectively who thinks that he isn't being tempted at all."
Just when we think we are not being tempted, that is the time of danger, and so it is with the church. We lean back on our own laurels and say, "That may be true of some churches, but it is not true of us. We are increased with goods and have need of nothing!"
This is to remind us that we must fight for what we have. Our little field of God's planting must have the necessary weapons and plenty of watchmen out there to drive off the crows and all sorts of creatures, to say nothing of the little insects that destroy the crops. We have to keep after them. We must keep our field healthy, and there is only one way to do that, and that is to keep true to the Word of God. We must constantly go back to the grass roots and get the Word into the church. When He is Come, 13,14.
"Lord, You have blessed us richly, but we've also seen the work of the enemy. Don't ever let us become complacent in Your blessing, Lord. Keep us vigilant that our field might stay healthy and the little weeds might never be allowed to take root. Amen."