“lying words.” The fact that the Temple of Yahweh was in Jerusalem was not a lie, but what the false prophets meant by those words was a lie. The false prophets were promoting that since the Temple of Yahweh was in Jerusalem, He would never let Jerusalem be conquered (cp. Micah 3:11). This idea was no doubt supported by the fact that God had miraculously protected Jerusalem during the time of Hezekiah, when 185,000 Assyrian soldiers were killed by an angel of Yahweh and Jerusalem was saved (2 Kings 19:32-35).
But God said that because of the sins of Judah the idea He would protect Jerusalem because of His Temple was “worthless” (Jer. 7:8). God told the people to reflect on Shiloh where God had earlier had the Tent of Meeting (“Tabernacle”), because Shiloh had been destroyed (Jer. 7:12-15), and Jerusalem would be conquered also (Jer. 7:15).