Yahweh speaks his message to all the people of the land by calling out to the land where they live. The title is repeated to call attention to the message. (See: [[rc://en/ta/man/translate/figs-apostrophe]])
Jehoiachin has several sons. This phrase, then, means it is as if he was childless. His children will not succeed him as king. AT: "It will be as if he did not have any children" (See: [[rc://en/ta/man/translate/figs-explicit]])