For Heshbon was the city of Sihon, etc. - It appears therefore that the territory now taken from Sihon by the Israelites was taken from a former king of Moab, in commemoration of which an epikedion or war song was made, several verses of which, in their ancient poetic form, are here quoted by Moses.

Arnon. Arnon is a stream which takes its rise in the mountains of Moab, and, by a north-west course, during which it receives the waters of several streams, runs into the Dead sea. It is now called Wady Modjeb, and divides the province of Pelka from that of Kerek, as it formerly divided the kingdoms of the Moabites and Amorites. Its principal source is at a short distance to the north-east of Katrance, a station of the Syrian Hadj, where it is called Seyl Sayde; and lower down it receives the name of Esseim el Kereim, or Szefye.

Messiah Suffering and Wounded for Us
Surely He hath borne our griefs, and carried our sorrows: ..... He was wounded for our transgressions, He was bruised for our iniquities: the chastisement of our peace was upon Him; and with His stripes we are healed. W hen our Lord was transfigured, Moses and Elijah appeared in glory and conversed with Him. Had we been informed of the interview only, we should probably have desired to know the subject of their conversation, as we might reasonably suppose it turned upon very interesting and important …
John Newton—Messiah Vol. 1

The Two Classes.
"Two men went up into the temple to pray."--Luke xvii. 10. I now want to speak of two classes: First, those who do not feel their need of a Saviour who have not been convinced of sin by the Spirit; and Second, those who are convinced of sin and cry, "What must I do to be saved?" All inquirers can be ranged under two heads: they have either the spirit of the Pharisee, or the spirit of the publican. If a man having the spirit of the Pharisee comes into an after-meeting, I know of no better portion …
Dwight L. Moody—The Way to God and How to Find It

Numbers
Like the last part of Exodus, and the whole of Leviticus, the first part of Numbers, i.-x. 28--so called,[1] rather inappropriately, from the census in i., iii., (iv.), xxvi.--is unmistakably priestly in its interests and language. Beginning with a census of the men of war (i.) and the order of the camp (ii.), it devotes specific attention to the Levites, their numbers and duties (iii., iv.). Then follow laws for the exclusion of the unclean, v. 1-4, for determining the manner and amount of restitution …
John Edgar McFadyen—Introduction to the Old Testament