John Calvin on Exodus 15:1

1. Then sang Moses. Moses introduced this song not only in testimony of his gratitude, but also in confirmation of the history; for the song which he dictated to the Israelites was not concerning an unknown event, but he brought them forward as eye-witnesses, that all ages might know that nothing thus far had been written which had not openly been declared by 600,000 men, besides their wives and children. Moses, therefore, set the example in accordance with his office, whilst the people, by singing with him, testified their approbation in a manner which admits of no contradiction. For’ to whom could they have lied, since they were each other’s witnesses, and the song was listened to by no strangers? Moses seems to mark their confidence by the repetition in the Hebrew, they “spoke, saying.” On this account, too, their confession, pronounced by all their mouths, deserves more credit, because the greater part of them soon after yielded to ingratitude: from whence we gather that it was only on compulsion that they gave God glory. But, although Moses was the author of the song, yet he does not say “I will sing” in his own person, but prescribes to all what each individual ought heartily to do.