Deuteronomy 2:26

Defeat of Sihon, King of Heshbon

2:26 Then I sent messengers from the Kedemoth ¹  Desert to King Sihon of Heshbon with an offer of peace:

Deuteronomy 20:10

20:10 When you approach a city to wage war against it, offer it terms of peace.

Deuteronomy 23:6

23:6 You must not seek peace and prosperity for them through all the ages to come.

¹ sn Kedemoth. This is probably Aleiyan, about 8 mi (13 km) north of the Arnon and between Dibon and Mattanah.