Hast... ? Figure of speech Erotesis, for emphasis.
there is. Some codices, with one early printed edition. Septuagint, Syriac, and Vulgate, read "and [so] there is".
Related Commentaries of Isaiah 40:28
Isaiah 40:28
28 Hast thou not known? hast thou not heard, that the everlasting God, the LORD, the Creator of the ends of the earth, fainteth not, neither is weary? there is no searching of his understanding.