How do the corners of a wheat field compare to the main harvest?

Les teaches that when a wheat farmer harvests the main part of his fields, he can fill bins with thousands and thousands of bushels. If he left the corners, as they did then, the amount would be just a small, small fraction by comparison. Les then brings it into the spiritual realm: Christ is the firstfruits, and that is accomplished. The largest number of people brought into God's harvest is in the Church Age, not the Old Testament. In the Old Testament economy, the little nation of Israel never had more than probably 10 million people, and only a few were true believers. Before the flood there were precious few believers; by the flood only 8 souls. Throughout Israel's history very few Jews percentage wise were believers. Even in Christ's earthly ministry, the upper room in Acts chapter 1 had 120, and in the Jerusalem area there must not have been more than these 120, though there may have been a few in Galilee. Compared to the millions brought in through the last 1900 years of preaching the Gospel of Grace, the corners are a small fraction.