What does Ezekiel 17:21 mean?

For he has despised the oath by breaking the covenant; and behold, he had given his hand, and yet has done all these things. He won’t escape.

“Therefore thus says the Lord Yahweh: ‘As I live, I will surely bring on his own head my oath that he has despised and my covenant that he has broken.

I will spread my net on him, and he will be taken in my snare. I will bring him to Babylon, and will enter into judgment with him there for his trespass that he has trespassed against me.

“Thus says the Lord Yahweh: ‘I will also take some of the lofty top of the cedar, and will plant it. I will crop off from the topmost of its young twigs a tender one, and I will plant it on a high and lofty mountain.

I will plant it in the mountain of the height of Israel; and it will produce boughs, and bear fruit, and be a good cedar. Birds of every kind will dwell in the shade of its branches.

All the trees of the field will know that I, Yahweh, have brought down the high tree, have exalted the low tree, have dried up the green tree, and have made the dry tree flourish. “‘I, Yahweh, have spoken and have done it.’”