Hath Israel no sons? - i. e., the Ammonites in seizing Gilead have acted as if the country had no rightful owner. The sons of Israel were to return from captivity, and the land was their hereditary property.
Their king - Milcom (and in Jeremiah 49:3), see the margin. The Ammonite god stands for the Ammonites just as Chemosh Jeremiah 48:7 is the equivalent of the Moabites.
Inherit - i. e., take possession of.