Verses 31-32: the Parable of the Grain of Mustard Seed AT 13:31-32{the Lord Compares the Kingdom of Heaven With a Grain of Mustard Seed, Which Is the Smallest of Seeds, but Grows Into the Greatest of Herbs. a Man Sows It in the Field, and It Grows Into Such a Great Tree That Even the Birds of the Air Find Ample Lodging in Its Branches

Already in this chapter, the Lord has given us enough information to understand the force of this parable. The field, as we have already seen, is the world, and the birds, wicked emissaries of Satan, come to subvert the truth of God's Word in the hearts of men (See also Gen. 15:11 and 2 Sam. 21:10.). They use whatever means they might in accomplishing their ends. One of their commonest tactics is to corrupt the truth while maintaining the form of the Word itself.
Now, what is there in the New Testament that might answer to these symbolic representations? On the day the assembly was first formed, there was only a handful of souls present—perhaps, 120. Then, as a result of Peter's preaching, some 3000 more souls were saved and added that same day. As time passed and the gospel seed was sown throughout the region and on to the uttermost parts of the earth, more and more souls were added to those first few thousand. Since then and down through the centuries, we have no way of knowing how many more souls have been saved. At any rate though, there have doubtless been millions and millions of them and, perhaps, more. What started out very small therefore has grown disproportionately into a great multitude of saved souls.
At the same time though, there have also been many souls, who, though not saved, have nevertheless professed to be Christians. Accordingly, what began as the house of God and the assembly, composed of a few real believers on the Lord Jesus Christ, has now grown into a great house, consisting not only of real believers, but also of false professors as well. (See 1 Tim. 3:15; 2 Tim. 2:19-20; 3:1-5.) As men became careless then, and even perverse, moral, doctrinal, and ecclesiastical evils were introduced into the house, where they were allowed to flourish until it became a great house. As such therefore, the house of Christian profession has become very large indeed and highly corrupted in both doctrine and practice. What is left of this house after the true assembly's rapture to heaven will be characterized as "the habitation of devils, and the hold of every foul spirit, and a cage of every unclean and hateful bird" (Rev. 18:2).