Numbers 21:27

Wherefore they that speak in proverbs say
The historical writers of those times, among the Amorites, who were usually poets, and wrote the history of the wars between the Moabites and Amorites in verse; as Homer among the Greeks wrote the wars of Troy; and the compositions of those ancient bards were short and compendious, and wrapped up in proverbial sayings, and enigmatical and figurative expressions, that they might be the better retained in memory, and therefore were called proverbialists. Jarchi says, they were Balaam and Beor that took up their parables, and said,

come into Heshbon;
which words are the beginning of the song, and in which the Amorites are represented as inviting Sihon, and his nobles, to enter Heshbon, which he had taken, and make it his royal seat; or as encouraging one another to go into it and repair it, having suffered much at the taking of it, which seems to be confirmed by what follows:

let the city of Sihon be built and prepared;
that is, let us set about rebuilding of the city, and let us fit it up for Sihon our king, and let it be called his city, and made the place of his residence, his palace, and where his court may be kept.