Charles Ellicott Commentary Jeremiah 17:3

"O my mountain in the field, I will give thy substance and all thy treasures for a spoil, [and] thy high places, because of sin, throughout all thy borders." — Jeremiah 17:3 (ASV)

My mountain in the field. —As in Jeremiah 21:13; Isaiah 2:2; Micah 4:2, a poetic phrase for Jerusalem or Zion, its greatness consisting not in its material elevation above the “field” or surrounding country, but in being “my mountain,” i.e., the mountain of Jehovah. These words predict the plunder of the city, perhaps especially the plunder of the Temple.

Your high places. —As having been from the time of Samuel onward the chief scene of the false worship of the people. The threat is repeated almost verbally from Jeremiah 15:13.