Psalms 114:5

"When Israel came out of Egypt, and the house of Jacob from among the strange people" [Psalm 114:1], "Judah was His sanctuary, and Israel His dominion" [Psalm 114:2]; "the sea saw that and fled, Jordan was driven back" [Psalm 114:3]. Think not that past deeds are related unto us, but rather that the future is predicted; since, while those miracles also were going on in that people, things present indeed were happening, but not without an intimation of things future....Some things he has related differently to what we have learned and read there: that he might not truly be thought to be repeating past acts rather than to be prophesying future things. For in the first place, we read not that the Jordan was driven back, but that it stood still on the side nearest the source of its streams, while the people were passing through; next, we read not of the mountains and hills skipping: all which he has added, and repeated. For after saying, "The sea saw that, and fled; Jordan was driven back:" he added, "The mountains skipped like rams, and the little hills like young sheep" [Psalm 114:4]: and then asks, "What ails you, O thou sea, that you fled, and thou, Jordan, that you were driven back?" [Psalm 114:5]. "You mountains, that you skipped like rams; and you little hills, like young sheep?" [Psalm 114:6].