Charles Ellicott Commentary 2 Kings 9:37

"and the body of Jezebel shall be as dung upon the face of the field in the portion of Jezreel, so that they shall not say, This is Jezebel." — 2 Kings 9:37 (ASV)

And the carcass of Jezebel. —This continuation of the prophecy is not given in 1 Kings 21:23. It is probably original; not “a free expansion” by Jehu, as Keil asserts.

Shall be. —It is questionable whether the Hebrew text is to be read as a rare ancient form (wəhāyaṯ); or simply as an instance of defective writing (wəhāyəṯâ). We prefer the second view.

As dung. —Compare to Psalms 83:10.

So that they shall not say. —Compare to Genesis 11:7 for the construction. The sense is, so that people will no longer be able to recognize her mangled remains.