If (as some read those words) we read this passage according to the original in the plural number: He is the holy Gods, meaning He, Jehovah existing in a threefold character of persons, the Holy Gods; this is a sweet and precious passage in confirmation of the Holy Trinity. Hear, O Israel, the Lord thy God is one Lord. A thing unnecessary to have been remarked, if at the same time it had not been suggested, that in this one eternal essence of the Godhead, there existed a plurality of persons. And hence, in the opening of the Bible, the phrase is the same plural: so in Solomon: Remember thy Creators; for so it is in the original. Ecclesiastes 12:1. Joshua's representing the difficulties, was not intended to put them off from their pious resolution; but only to forewarn them of the difficulty. Our dear Lord told his disciples somewhat similar, when he represented his service as taking up a cross, plucking out an eye, and cutting off an arm.
Related Commentaries of Joshua 24:19
Joshua 24:19-20
19 And Joshua said unto the people, Ye cannot serve the LORD: for he is an holy God; he is a jealous God; he will not forgive your transgressions nor your sins.
20 If ye forsake the LORD, and serve strange gods, then he will turn and do you hurt, and consume you, after that he hath done you good.