of the hills] Dwelling on hills, and protecting their dwelling places. This they say, because of the many high places which the Israelites had on hills.
in the plain] For Samaria (about which they fought before) was on a mountain.
and surely] Heb. if not. A concise speech ordinarily used in forms of oaths: for making up the sense, something must be supplied; as see, or trie if we prove not stronger. So Genesis 14:23.