John Gill Commentary Deuteronomy 2:37

"only to the land of the children of Ammon thou camest not near; all the side of the river Jabbok, and the cities of the hill-country, and wheresoever Jehovah our God forbade us." — Deuteronomy 2:37 (ASV)

Only unto the land of the children of Ammon you came not ,
&c.] Which was then in their possession; otherwise what Sihon had took away from them, that the children of Israel came into and enjoyed, as before observed, (Deuteronomy 2:19)

nor unto any place of the river Jabbok ;
any town or city situated on this river, which was the border of the children of Ammon, (Deuteronomy 3:16) , (See Gill on Genesis 32:22),

nor unto the cities in the mountains ;
much less did they penetrate into the innermost parts of their country, the mountainous part thereof, and the cities there:

nor unto whatsoever the Lord our God forbad us :
whether in Edom, Moab, or Ammon, particularly the latter, of which he is more especially and peculiarly speaking.