John Calvin preaches about the challenges faced by godly teachers who may feel discouraged when they do not see the immediate results of their labor. He emphasizes the importance of serving God faithfully, even when it seems like their efforts are in vain, and encourages them to continue their work diligently without being disheartened by the world's malice. Calvin highlights the ingratitude of the world towards the gospel, attributing the lack of fruitfulness not to the message itself but to the obstinacy and rejection of God's grace by people. He challenges those who criticize the effectiveness of the gospel, reminding them that the responsibility lies with individuals who hinder the impact of the Word through their unbelief and actions.

Then I said, I have laboured in vain, I have spent my strength for nought, and in vain: yet surely my judgment is with the Lord, and my work with my God. —Isaiah 49:4 "But my judgment is before Jehovah." Although we do not clearly see the fruit of our labors, yet we are enjoined to be content on this ground, that we serve God, to whom our obedience is acceptable. Christ exhorts and encourages godly teachers to strive earnestly till they rise victorious over this temptation, and, laying aside the malice of the world, to advance cheerfully in the discharge of duty, and not to allow their hearts to languish through weariness. "If therefore the Lord be pleased to make trial of our faith and patience to such an extent that it shall seem as if we wearied ourselves to no purpose, yet we ought to rely on this testimony of our conscience. And if we do not enjoy this consolation, at least we are not moved by pure affection, and do not serve God, but the world and our own ambition. Yet it ought to be observed that here Christ and the Church accuse the whole world of ingratitude. For the Church complains to God in such a manner as to remonstrate with the world, because no good effect is produced in it by the doctrine of the gospel, which in itself is efficacious and powerful. Yet the whole blame rests on the obstinacy and ingratitude of men, who reject the grace of God offered to them, and of their own accord choose to perish. Let those persons now go and accuse Christ, who say that the gospel yields little fruit, and who defame the doctrine of the word by wicked slanders, and who throw ridicule on our labors as vain and unprofitable, and who allege that, on the contrary, they excite men to sedition, and lead them to sin with less control. Let them consider, I say, with whom they have to do, and what advantage they gain by their impudence, since men alone ought to bear the blame, who, as far as lies in their power, render the preaching of the Word unprofitable. —Commentaries