What does Ezekiel 6:13 mean?

When their dead bodies are lying among their idols and around their altars—on every hilltop, mountain, under every green tree, and every leafy oak where they offered sacrifices to their disgusting idols—then you'll know that I am the Lord. Ezekiel 6:13 - Modern Text Bible

(Their idols won't save them; their destruction will be a clear sign that God alone is real and in control.)