(Questions and Answers)
Ask Torah Teacher Ariel
(Note: all quotations are taken from the Complete Jewish Bible, translation by David H. Stern, Jewish New Testament Publications, Inc., unless otherwise noted)
What are the "high places" and the groves?
First, unless you are already familiar with the passage, read Isaiah 57:3-13. Without needing to go into a lot of detail, the "high places", alluded to in verse seven and "groves", alluded to in verse 5, were idolatrous locations for the pagans to worship their false gods. Often this worship took on the form of lewd sexual practices involving temple prostitutes and high priests; it also involved infants and children sometimes ("Oy-vey!"). The Torah explicitly forbade the Children of Israel to imitate or join in on these practices. Sometimes the worshippers object of attention was to the heavenly luminaries. Other time it was to gods said to personify the luminaries (i.e. sun-god worship as opposed to worship of the sun itself). Going to a high place brought the worshipper closer to his object of worship, or to heaven itself. Sacrifice to the sun was common in that time. Burning the "sacrifice" alive was also common. Meeting under the leafy branches of trees hid the sometimes-gross immoral acts of the sexual worshippers. So one can easily see why HaShem hated these pagan practices. In fact, in my opinion, the tower mentioned in Genesis 11:4 is the first recorded "high place" built by men with wrong intentions.
Torah Teacher Ariel ben-Lyman HaNaviy