John Calvin Commentary Isaiah 57:7

"Upon a high and lofty mountain hast thou set thy bed; thither also wentest thou up to offer sacrifice." — Isaiah 57:7 (ASV)

Upon a lofty and high mountain. He again repeats that metaphor at which we have previously glanced. Superstitious persons commit fornication with their idols because by forsaking the simplicity of the word, they violate the bond of that holy marriage into which God has entered with them and prostitute themselves to Satan.

But now Isaiah intended to express something more; for when he says that they set up their bed on a lofty place, he means that they are not at all ashamed of their shameful conduct. As a harlot who has lost all shame does not dread the sight of men and does not care about her reputation, so they openly and shamefully committed fornication in a lofty and conspicuous place.

He compares altars and groves to “beds” on which that accursed crime is committed, and he compares men who sacrifice on them to impudent and abandoned harlots. As for the opinion held by some that this relates to the couches on which they reclined at their sacrificial feasts, there is no good foundation for it.

To offer a sacrifice. Here he describes plainly that kind of fornication which he rebukes: namely, that they offered sacrifices to idols. They imagined, indeed, that in doing so they were rendering obedience to God; but the Lord rejects all that men contrive according to their own pleasure and abhors that licentiousness.