Albert Barnes 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 - The design of this verse and the following is to show the extent, the prevalence, the publicity, and the grossness of their idolatry. The language is such that it would appropriately express adulterous intercourse and is designed to show the abhorrence God held for their conduct. The language is easy to understand, and it would not be proper to go into an extended explanation of the phrases used.

It is common in the Scriptures to compare idolatry among the people of God with unfaithfulness to the marriage vow. The declaration that they had placed their bed on a high mountain means that in the rites of idolatrous worship, there was no concealment. It was public and shameless.