The seal, however, has another use than that of marking and identifying property. It is a symbol of assurance. It is the answer to a challenge. It is in this sense that it is easiest to apply the figure to baptism. Baptism does not, indeed, carry with it the actual possession of all these spiritual features; it is not even, as an _opus operatum_, the implanting of them in the soul; but it is a divine pledge that they are within our reach; we can appeal to it as an assurance that God has come to us in His grace, has claimed us as His own, and is willing to conform us to the image of His Son. In this sense, it is legitimate and natural to call it God's seal upon His people. (4) Side by side with "He sealed us," the Apostle writes, "He gave the earnest of the Spirit in our hearts." After what has been said, it is obvious that this is another aspect of the same thing. We are sealed with the Spirit, and we get the earnest of the Spirit. In other words, the Spirit is viewed in two characters: first, as a seal; and then as an earnest. This last word has a very ancient history. It is found in the Book of Genesis (xxxviii. 18: עֵרָבוׄן), and was carried, no doubt, by Phœnician traders, who had much occasion to use it, both to Greece and Italy. From the classical peoples it has come more or less directly to us. It means properly a small sum of money paid to clench a bargain, or to ratify an engagement. Where there is an earnest, there is more to follow, and more of essentially the same kind--that is what it signifies. Let us apply this now to the expression of St. Paul, "the earnest of the Spirit." It means, we must see, that in the gift of this Spirit, in that measure in which we now possess it, God has not given all He has to give. On the contrary, He has come under an obligation to give more: what we have now is but "the firstfruits of the Spirit" (Rom. viii. 23). It is an indication and a pledge of what is yet to be, but bears no proportion to it. All we can say on the basis of this text is, that between the present and the future gift--between the earnest and that which it guarantees--there must be some kind of congruity, some affinity which makes the one a natural and not an arbitrary reason for believing in the other.