On high — He speaks not so much of height of place, as of dignity and power, in which sense also he mentions the lofty city in the next clause. Lofty city — Which may be understood either of proud Babylon, or of all the strong and stately cities of God's enemies.
Related Commentaries of Isaiah 26:5
Isaiah 26:5
5 For he bringeth down them that dwell on high; the lofty city, he layeth it low; he layeth it low, even to the ground; he bringeth it even to the dust.