John Calvin Commentary Isaiah 17:10

"For thou hast forgotten the God of thy salvation, and hast not been mindful of the rock of thy strength; therefore thou plantest pleasant plants, and settest it with strange slips." — Isaiah 17:10 (ASV)

Because thou hast forgotten the God of thy salvation. He shows the reason why the Lord exercises such severity against the Ten Tribes, so that they may not complain of being unjustly afflicted or too harshly treated. The sum of what is stated is that all these evils come to them because they have wickedly despised God.

It was excessively base and altogether inexcusable ingratitude, after having received so many favors, to prostitute their hopes to heathen nations and to idols, as if they had never in any respect experienced the love of God. Indeed, no unbelievers, when they are called to account, will vindicate themselves from the charge of offering an insult to God by wandering after creatures. But the argument was applicable, in a special manner, to the people of Israel, to whom God had revealed Himself in such a way that they ought to have abandoned all the deceptions of the world and relied on His grace alone. They are therefore justly accused of ingratitude for having buried in forgetfulness the object of true faith. Indeed, when God has once allowed us to taste the delight of His goodness, if it gains a place in our hearts, we shall never be drawn away from it to anything else. Hence it follows that those who, not being satisfied with the true God, are unsteady and driven about in all directions are convicted of ingratitude, for in this manner they despise His invaluable grace.

Accordingly, the Prophet expressly calls Him the God of salvation and the God or Rock of strength—צור (tsūr) has both meanings—for it was a monstrous thing that they did not remain faithful to God, who had so often preserved them, as it were, with an outstretched hand. When he adds that they had not been mindful, this is an amplification, for he indirectly charges them with base slothfulness in not considering the many ways God had formerly made His kindness known to them.

Therefore thou shalt plant. Next follows the punishment, so that they might not think that this ingratitude would remain unpunished. That is, because they forsook the fountain of all good, though they labor to obtain food, they will still be consumed by famine and hunger, for the enemy will either carry away or destroy all that is obtained with great labor. This passage is taken from Moses, for it is a curse pronounced amidst other curses.

The fruit of thy land, and all thy labors, shall a nation which thou knowest not eat up. (Deuteronomy 28:33).

Hence we see what I have often mentioned before: that the prophets borrow many things from Moses and are the true interpreters of the law. He speaks of choice vines and branches taken from them, because the greatness of the loss aggravates the sorrow.