Though Babylon should mount up to heaven, and though she should fortify the height of her strength, yet from me shall spoilers come unto her, saith the LORD.
Though Babylon should mount up to heaven - (cf. Obadiah 1:4 as to Edom; Amos 9:2, "Though they climb up to heaven, thence will I bring them down").
Though ... yet from me shall spoilers come unto her, saith the Lord. We are not to measure God's power by what seems to our perceptions natural or probable.