John Calvin Commentary Luke 17:13

"and they lifted up their voices, saying, Jesus, Master, have mercy on us." — Luke 17:13 (ASV)

Jesus, Master³³⁸

It is evident that all of them possessed some measure of faith, not only because they implore Christ's assistance, but also because they honor him with the title of Master. That they used that expression sincerely, and not in hypocrisy, can be inferred from their ready obedience. For, although they perceive that the filthy scab still remains in their flesh, as soon as they are commanded to show themselves to the priests, they do not refuse to obey.

Furthermore, without the influence of faith, they would never have set out to show themselves to the priests; for it would have been absurd for them to present themselves to the judges of leprosy to attest that they had been cleansed, if Christ's promise had been regarded by them as no more valuable than a mere inspection of the disease. They bear a visible leprosy in their flesh; yet, trusting to Christ’s word alone, they do not hesitate to declare that they are clean.

Therefore, it cannot be denied that some seed of faith had been implanted in their hearts. Now, although it is certain that they were not regenerated by the Spirit of adoption, there is no absurdity in supposing that they had some beginnings of piety.

There is all the more reason to fear that sparks of faith, which appear in us, may be extinguished. For, although living faith, which has its roots deeply fixed by the Spirit of regeneration, never dies, we have previously seen that many conceive a temporary faith, which immediately disappears.

Above all, it is a very common ailment that when we are urged by strong necessity, and when the Lord himself prompts us by a secret movement of the Spirit, we seek God; but when we have obtained our wishes, ungrateful forgetfulness swallows up that feeling of piety. Thus, poverty and hunger produce faith, but abundance kills it.

³³⁸ “Iesus, nostre Maistre;” — “;” — “Jesus,our our Master.”