Charles Ellicott Commentary Ezekiel 17:19

"Therefore thus saith the Lord Jehovah: As I live, surely mine oath that he hath despised, and my covenant that he hath broken, I will even bring it upon his own head." — Ezekiel 17:19 (ASV)

Mine oath ... my covenant. —Zedekiah’s oath and covenant to Nebuchadnezzar are called the Lord’s, because made in the Lord’s name, and also because He had commanded them. Rebellion against Nebuchadnezzar was, therefore, under the circumstances, apostasy from the Lord Himself.

With Ezekiel 17:21 the explanation of the parable ends. What follows is a distinct Messianic prophecy, which, although couched in the same figurative language, has nothing corresponding to it either in the parable or in its explanation.