If his children - His posterity; his successors on the throne.
Forsake my law - If they are not regulated by it in the administration of their government, and in their private lives. It is here supposed that they might forsake his law, or fail to observe it; but still there is the assurance that the power would not depart permanently from the successors of David, but that it would be restored ultimately to that line, and be permanent and eternal.
And walk not in my judgements - And do not obey my commandments.