John Calvin on Luke 5:6-7

Luke 5:6. They inclosed a great multitude of fishes. The design of the miracle undoubtedly was, to make known Christ’s divinity, and thus to induce Peter and others to become his disciples. But we may draw from this instance a general instruction, that we have no reason to be afraid lest our labor should not be attended by the blessing of God and desirable success, when it is undertaken by the authority and guidance of Christ. Such was the multitude of fishes, that the ships were sinking, and the minds of the spectators were thus excited to admiration: for it must have been in consequence of the divine glory of Christ manifested by this miracle, that his authority was fully acknowledged.