en_tn_condensed/isa/02/15.md

high tower ... impregnable wall

These refer to things people would build around their cities so they could defend themselves against their enemies. They are pictures of the Israelites' pride and belief that they had no need for Yahweh and could stand against any punishment Yahweh would mete out to them for their sins.

impregnable wall

"wall that nothing can break down or go through"