Midrasch zu Dewarim 15:15

(Devarim 15:15) "And you shall remember that you were a slave in the land of Egypt": I bestowed upon you (the spoils of Egypt upon your leaving Egypt), and again (at the splitting of the sea) — so, you bestow upon him (once) and then, again. Just as in Egypt I bestowed upon you with a lavish hand, so, you. And thus is it written (Psalms 68:14) "Even for those of you who lie among the sheepfolds, there are wings of a dove sheathed in silver" — the spoils of Egypt. "and its pinions of fine gold" — the spoils of the sea. (Song of Songs 1:11).