That is why the poets say:
The narrative introduces a saying from the poets about Heshbon.
This verse prepares the quoted taunt-song.
21Then Israel sent messengers to Sihon king of the Amorites, saying, 22“Let us pass through your land. We will not turn aside into any field or vineyard, or drink water from any well. We will stay on the King’s Highway until we have passed through your territory.” 23But Sihon would not let Israel pass through his territory. Instead, he gathered his whole army and went out to confront Israel in the wilderness. When he came to Jahaz, he fought against Israel. 24And Israel put him to the sword and took possession of his land, from the Arnon to the Jabbok — but only up to the border of the Ammonites, because it was fortified. 25Israel captured all the cities of the Amorites and occupied them, including Heshbon and all its villages. 26Heshbon was the city of Sihon king of the Amorites, who had fought against the former king of Moab and taken all his land as far as the Arnon. 27That is why the poets say: 28For a fire went out from Heshbon, 29Woe to you, O Moab! 30But we have overthrown them;