Albert Barnes Commentary Psalms 136:16

"To him that led his people through the wilderness; For his lovingkindness [endureth] for ever:" — Psalms 136:16 (ASV)

To him which led his people through the wilderness — for all the manifestations of his care during a period of forty years.

For his mercy ... — that is, his mercy was to be measured by all the protection extended over them; by all the provision made for their needs; by all that God did to defend them; by all his interposition when attacked by their enemies; by safely bringing them to the land to which he had promised to conduct them.