John Calvin Commentary Deuteronomy 32:2

"My doctrine shall drop as the rain; My speech shall distil as the dew, As the small rain upon the tender grass, And as the showers upon the herb." — Deuteronomy 32:2 (ASV)

My doctrine shall drop as the rain. Some, as I think improperly, interpret the future tense here as the optative mood.²⁴⁸ For in this splendid praise, he rather celebrates—in order to commend his doctrine—the fruitfulness²⁴⁹ that is actually imparted to it by the Holy Spirit, than asks for it to be given to him. Indeed, my readers must immediately perceive that such a request would have been by no means appropriate.

He therefore compares his speech to rain or dew, as if he had said that if only the people were like the soil—soft and prepared—he would deliver doctrine to them that would irrigate them for abundant fruitfulness.

Although this expression refers especially, and κατ’ ἐξοχήν, to the Song, its force and appropriateness still extend to all divine teaching. For God never speaks except to make people fruitful in good works, just as, by instilling moisture and vigor into the earth through rain, He makes it fertile to produce fruit.

But, like rocks and stones that imbibe no moisture from the most abundant rains, so many are hindered by their own perversity from being fertilized by spiritual irrigation. Therefore, Moses indirectly throws the blame on the Israelites if the doctrine of this Song should drop upon them in vain.

²⁴⁸ So the LXX., V., Vatablus, Junius, and others. Ainsworth combines the two, and says, “., Vatablus, Junius, and others. Ainsworth combines the two, and says, “shall drop, or or let it drop, as being a wish, and also a promise, that his doctrine should be profitable and effectual,” etc.as being a wish, and also a promise, that his doctrine should be profitable and effectual,” etc.

²⁴⁹ “L’eloquence.” —— Fr.