Therefore, &c.— The prophet here foretels the unfortunate event of their enterprize; namely, that their reliance on the strength of So, the Pharaoh or king of Egypt, should avail them nothing, but turn out to their confusion. See 2 Kings 17:4. This is more fully set forth in the subsequent verses.
Related Commentaries of Isaiah 30:3
Isaiah 30:3
3 Therefore shall the strength of Pharaoh be your shame, and the trust in the shadow of Egypt your confusion.