John Calvin Commentary Psalms 18:13

"Jehovah also thundered in the heavens, And the Most High uttered his voice, Hailstones and coals of fire." — Psalms 18:13 (ASV)

Jehovah thundered. David here repeats the same thing in different words, declaring that God thundered from heaven; and he calls the thunder the yoke of God, so that we may not suppose it is produced merely by chance or by natural causes, independent of the appointment and will of God.

Philosophers, it is true, are well acquainted with the intermediate or secondary causes from which thunder proceeds: namely, that when cold and humid vapours obstruct the dry and hot exhalations in their upward course, a collision takes place, and by this, together with the noise of the clouds rushing against each other, the rumbling thunder-peal is produced.

But David, in describing the phenomena of the atmosphere, rises, under the guidance of the Holy Spirit, above the mere phenomena themselves, and represents God to us as the supreme governor of the whole, who, at his will, penetrates into the hidden veins of the earth and from there draws out exhalations; who then, dividing them into different kinds, disperses them through the air; who again collects the vapours together and sets them in conflict with the subtle and dry heats, so that the thunder which follows seems to be a loud, pealing voice proceeding from his own mouth.

The song in 2 Samuel also contains the repetition to which we have referred in the beginning of our remarks on this verse; but the sense of this and the preceding verse, and of the corresponding verses in Samuel, is entirely similar. We should remember what I have said before: David, under these figures, describes to us the dreadful power of God, in order to better exalt and magnify the divine grace manifested in his deliverance.

He declares a little later that this was his intention. For, when speaking of his enemies, he says (Psalms 18:14) that they were scattered, or put to flight, by the arrows of God; as if he had said, "They have been overthrown, not by the hands or swords of men, but by God, who openly launched his thunderbolts against them."

Not that he means to affirm that this happened literally, but he speaks in this metaphorical language because those who were uninstructed and slow to acknowledge the power of God could not otherwise be brought to perceive that God was the author of his deliverance.

The import of his words is this: "Whoever does not acknowledge that I have been preserved by the hand of God might as well deny that it is God who thunders from heaven, and abolish his power which is manifested in the whole order of nature, and especially in those wonderful changes we see taking place in the atmosphere."

Since God shoots lightnings as if they were arrows, the Psalmist first employed this metaphor, and then he expressed the matter plainly by its proper name.