John 4:36-38

And certainly both considerations ought greatly to encourage the ministers of the word, that they may never sink under the toil, when they hear that a crown of glory is prepared for them in heaven, and know that the fruit of their harvest will not only be precious in the sight of God, but will also be eternal. It is for this purpose that Scripture everywhere mentions reward, and not for the purpose of leading us to judge from it as to the merits of works; for which of us, if we come to a reckoning, will not be found more worthy of being punished for slothfulness than of being rewarded for diligence? To the best laborers nothing else will be left than to approach to God in all humility to implore forgiveness. But the Lord, who acts towards us with the kindness of a father, in order to correct our sloth, and to encourage us who would otherwise be dismayed, deigns to bestow upon us an undeserved reward.

This is so far from overturning justification by faith that it rather confirms it. For, in the first place, how comes it that God finds in us any thing to reward, but because He has bestowed it upon us by his Spirit? Now we know that the Spirit is the earnest and pledge of adoption, (Ephesians 1:14.) Secondly, how comes it that God confers so great honor on imperfect and sinful works but because, after having by free grace reconciled us to himself, He accepts our works without any regard to merit, by not imputing the sins which cleave to them? The amount of this passage is, that the labor which the Apostles bestow on teaching ought not to be reckoned by them hard and unpleasant, since they know that it is so useful and so advantageous to Christ and to the Church.

That he who soweth, and he who reapeth, may rejoice together. By these words Christ shows that the fruit which the Apostles will derive from the labors of others cannot give just ground of complaint to any person. And this additional statement deserves notice; for if in the world the groans of those who complain that the fruit of their labor has been conveyed to another do not hinder the new possessor from cheerfully reaping what another has sown, how much more cheerful ought the reapers to be, when there is mutual consent and mutual joy and congratulation?

But, in order that this passage may be properly understood, we must comprehend the contrast between sowing and reaping The sowing was the doctrine of the Law and the Prophets; for at that time the seed thrown into the soil remained, as it were, in the blade; but the doctrine of the Gospel, which brings men to proper maturity, is on that account justly compared to the harvest. For the Law was very far from that perfection which has at length been exhibited to us in Christ. To the same purpose is the well-known comparison between infancy and manhood which Paul employs, when he says, that

the heir, as long as he is a child, differeth not from a servant, though he be lord of all, but is under tutors and governors until the time appointed by the father, (Galatians 4:1, 2.)

In short, since the coming of Christ brought along with it present salvation, we need not wonder if the Gospel, by which the door of the heavenly kingdom is opened, be called the harvest of the doctrine of the Prophets. And yet it is not at all inconsistent with this statement, that the Fathers under the Law were gathered into God’s barn; but this comparison must be referred to the manner of teaching; for, as the infancy of the Church lasted to the end of the Law, but, as soon as the Gospel had been preached, it immediately arrived at manhood, so at that time the salvation began to ripen, of which the sowing only had been accomplished by the Prophets.

But, as Christ delivered this discourse in Samaria, he appears to extend the sowing more widely than to the Law and the Prophets; and there are some who interpret these words as applying equally to the Jews and to the Gentiles. I acknowledge, indeed, that some grains of piety were always scattered throughout the whole world, and there can be no doubt that — if we may be allowed the expression — God sowed, by the hand of philosophers and profane writers, the excellent sentiments which are to be found in their writings. But, as that seed was degenerated from the very root, and as the corn which could spring from it, though not good or natural, was choked by a huge mass of errors, it is unreasonable to suppose that such destructive corruption is compared to sowing. Besides, what is here said about uniting in joy cannot at all apply to philosophers or any persons of that class.

Still, the difficulty is not yet solved, for Christ makes special reference to the Samaritans. I reply, though everything among them was infected by corruptions, there still was some hidden seed of piety. For whence does it arise that, as soon as they hear a word about Christ, they are so eager to seek him, but because they had learned, from the Law and the Prophets, that the Redeemer would come? Judea was indeed the Lord’s peculiar field, which he had cultivated by the Prophets, but, as some small portion of seed had been carried into Samaria, it is not without reason that Christ says that there also it reached maturity. If it be objected that the Apostles were chosen to publish the Gospel throughout the whole world, the reply is easy, that Christ spoke in a manner suited to the time, with this exception, that, on account of the expectation of the fruit which already was nearly ripe, he commends in the Samaritans the seed of prophetic doctrine, though mixed and blended with many weeds or corruptions.