Exodus 15:18 - Coke's Commentary on the Holy Bible

The Lord shall reign for ever and ever— An exulting strain; expressing the absolute sovereignty of Jehovah, which he had demonstrated by this signal overthrow of the Egyptians, as the next verse declares; where the reason is given for this triumphant assertion; for the horse of Pharaoh, &c. This 19th verse contains what the Greeks call the epiphonema of the song, which includes the whole subject of it, like the first chorus; as we have remarked upon the place. The conclusion being simple, and less figurative than the former part of the song, has led some writers to suppose, that the poetical part ends at the 18th verse: but this is a mistake; as the 19th verse is, in the Hebrew, no less metrical than the others.