Charles Ellicott Commentary Isaiah 55:5

"Behold, thou shalt call a nation that thou knowest not; and a nation that knew not thee shall run unto thee, because of Jehovah thy God, and for the Holy One of Israel; for he hath glorified thee." — Isaiah 55:5 (ASV)

Thou shalt call a nation. —The calling of the Gentiles and the consequent expansion of the true idea of Israel is again dominant. The words sound like an echo from Psalm 18:43.

Because of the Lord thy God ... —The words are repeated, as expressing a thought on which the prophet loved to dwell, in Isaiah 60:9.