Jamieson, Fausset & Brown, on Josh 3:5

“And Josue said to the people: Be ye sanctified: for tomorrow the Lord will do wonders among you.”

“Joshua said unto the people--rather "had said," for as he speaks of "to-morrow," the address must have been made previous to the day of crossing, and the sanctification was in all probability the same as Moses had commanded before the giving of the law, consisting of an outward cleansing (Exo 19:10-15) preparatory to that serious and devout state of mind with which so great a manifestation should be witnessed.”

Imported from an open dataset — not yet checked against the printed edition.