Charles Ellicott Commentary Deuteronomy 3:6

"And we utterly destroyed them, as we did unto Sihon king of Heshbon, utterly destroying every inhabited city, with the women and the little ones." — Deuteronomy 3:6 (ASV)

We utterly destroyed them. —Devoted them, made them chêrem, as above (Deuteronomy 2:34).