Midrasch zu Jeschijahu 7:12

Rabbi Eliezer said: Not only concerning the water does the Scripture say that "the waters should bring forth abundantly" (Gen. 1:20), but also concerning the birds which are compared with water, as it is said, "And the uproar of many peoples, which roar like the roaring of the seas" (Isa. 17:12), and just as the waters brought forth abundantly on the fifth day, likewise in the future will the nations of the world swarm in the fifth world, and they will fight one another to destroy (one another), as it is said, "And they were broken in pieces, nation against nation, and city against city; for God did vex them with all adversity" (2 Chron. 15:6). What is written (immediately) afterwards? The Salvation of Israel (is mentioned), as it is said, "But be ye strong; and your hands shall not be slack" (2 Chron. 15:7).