“And Israel smote him with the edge of the sword, and possessed his land from Arnon unto Jabbok, even unto the children of Ammon: for the border of the children of Ammon was strong.”
King James Version (KJV)
21:24 From Arnon - Or, which reached from Arnon; and so here is a description or limitation of Sihon's conquest and kingdom, that is, extended only from Arnon, unto the children of Ammon; and then the following words, for the border of the children of Ammon was strong, come in very fitly, not as a reason why the Israelites did not conquer the Ammonites, for they were absolutely forbidden to meddle with them, #Deu 3:8|, but as a reason why Sihon could not enlarge his conquests to the Ammonites, as he had done to the Moabites. Jabbok - A river by which the countries of Ammon and Moab were in part bounded and divided. Strong - Either by the advantage of the river, or by their strong holds in their frontiers.