Question: "What is the significance of high places in the Bible?"
Answer: High places, very simply, were places of worship on elevated pieces of ground or raised altars in low land such as a valley. High places were originally dedicated to idol worship (Numbers 33:52; Leviticus 26:30) especially among the Moabites (Isaiah 16:12). These shrines often included an altar and a sacred object such as a stone pillar or wooden pole in various shapes, identified with the object of worship (animals, constellations, goddesses, and fertility deities).
The Israelites, forever turning away from God, practiced Molech worship and built high places for Baal (Jeremiah 32:35). Although Solomon built the temple of God in Jerusalem, he later established idolatrous high places for his foreign wives outside of Jerusalem and worshiped with them, causing him the loss of the kingdom (1 Kings 11:11). The people were still sacrificing at the pagan high places before the temple was built, and Solomon joined them. After the Lord appeared to him in a dream at Gibeon, the king returned to Jerusalem and sacrificed offerings; however, he continued to waver between the two places of worship.
Not all high places were dedicated to idol worship. They played a major role in Israelite worship, and the earliest biblical mention of a site of worship, later called a “high place,” is found in Genesis 12:6–8 where Abram built altars to the Lord at Shechem and Hebron. Abraham built an altar in the region of Moriah and was willing to sacrifice his son there (Genesis 22:1–2). This site is traditionally believed to be the same high place where the temple of Jerusalem was built. Jacob set up a stone pillar to the Lord at Bethel (Genesis 28:18–19), and Moses met God on Mt. Sinai (Exodus 19:1–3).
Joshua set up stone pillars after crossing the Jordan (Joshua 4:20) and considered this a high place of worship because the Israelites “came up from” the Jordan onto higher ground. The high places were visited regularly by the prophet Samuel (1 Samuel 7:16). High places as sites of Canaanite idol worship (Judges 3:19) extended into the period of Elijah (1 Kings 18:16–40). God would name only one high place where sacrifice was authorized, and that was the temple in Jerusalem (2 Chronicles 3:1). God commanded that all other high places be destroyed. King Josiah destroyed them in 2 Kings 22—23.