Charles Ellicott Commentary Psalms 136:19

"Sihon king of the Amorites; For his lovingkindness [endureth] forever;" — Psalms 136:19 (ASV)

Sihon. —Literally, to Sihon. Evidently the composer, after beginning so many verses with the preposition, placed it here inadvertently, from which it was copied in Psalms 135:11.