John Calvin Commentary Psalms 107:20

"He sendeth his word, and healeth them, And delivereth [them] from their destructions." — Psalms 107:20 (ASV)

He sends his word. Again, in saying that they are delivered from destruction, the prophet shows that he is alluding here to those diseases which, in human opinion, are incurable, and from which few are delivered. Besides, he contrasts God’s assistance with all the remedies that humans have the power to apply; as if he were saying that, their disease having baffled the skill of earthly physicians, their recovery has been entirely due to the exertion of God’s power.

It is also proper to notice the manner in which their recovery is effected: God has only to will it, or to speak the word, and instantly all diseases, and even death itself, are expelled. I do not regard this as exclusively referring to the faithful, as many expositors do.

Indeed, I acknowledge that being the subjects of bodily care is of comparatively little consequence to us if our souls still remain unsanctified by the word of God; and therefore, the prophet intends for us to consider God's mercy as extending even to the evil and unthankful.

The meaning of the passage, therefore, is that diseases neither come upon us by chance, nor are to be ascribed to natural causes alone, but are to be viewed as God’s messengers executing his commands; so that we must believe that the same person who sent them can easily remove them, and for this purpose, he only has to speak the word.

And since we now perceive the drift of the passage, we ought to attend to the very appropriate analogy it contains. Bodily illnesses are not removed except by the word or command of God; much less are human souls restored to the enjoyment of spiritual life, unless this word is apprehended by faith.

And let them sacrifice. This clause is added by way of explanation, to express more strongly how God is robbed of his due if his providence is not recognized in the matter of sacrifice. Even nature itself teaches that some kind of homage and reverence is due to God; this is acknowledged by the pagans themselves, who have no other instructor than nature.

We also know that the practice of offering sacrifices has prevailed among all nations; and doubtless, it was by the observance of this ritual that God intended to preserve in the human family some sense of piety and religion. To acknowledge God's bounty and beneficence is the most acceptable sacrifice that can be presented to him; therefore, the prophet intends to recall to this subject the attention of insensitive and indifferent people.

I do not deny that there may also be an allusion to the ceremonial law; but since sacrifices formed part of religious exercises in the world at large, he charges those with ingratitude who, after having escaped from some imminent peril, forget to celebrate the praises of their Great Deliverer.