To Autolycus 2.16

On the fifth day the living creatures of the waters came into being, and through them too the manifold wisdom of God is shown. For who could count their multitude and their endlessly varied offspring? Moreover, the creatures that came from the waters were blessed by God, so that this too might be a sign that human beings would receive repentance and forgiveness of sins through water and the washing of regeneration: all who come to the truth, are born again, and receive a blessing from God. But the sea monsters and the birds that eat flesh are an image of the greedy and the lawbreakers. For though the water creatures and the birds are of one nature, some of them remain in their natural state and do not harm those weaker than themselves, but keep the law of God and eat of the seeds of the earth; while others transgress the law of God by eating flesh, and harm those weaker than themselves. So too the righteous, keeping the law of God, bite no one and harm no one, but live holy and righteous lives; while robbers, murderers, and the godless are like sea monsters and wild beasts and flesh-eating birds, for by their strength they devour those weaker than themselves. The brood of water creatures and creeping things, then, though it shared in God's blessing, received no distinctive property of its own.