Midrash su Giosuè 2:9

"Thou stretchedst out thy right hand, the earth swallowed them" (Ex. 15:12). The Holy One, blessed be He, told the earth to bury the slain. (The earth) said unto Him: Sovereign of all worlds! The waters have killed them, let the waters swallow them. He answered (the earth) saying: On this occasion receive them; on another occasion such that be killed by thee in the future will I cast into the sea, namely, Sisera and all his host, these will I cast into the sea, as it is said, "The river Kishon swept them away, that ancient river" (Judg. 5:21 ). (The earth) continued, saying to Him: Give me the oath by Thy right hand, that Thou wilt not claim them at my hand. The Holy One, blessed be He, put forth His right hand, and swore to the earth that He would not claim them, as it is said, "Thou stretchedst out thy right hand, the earth swallowed them" (Ex. 15:12). All the kings of the earth heard of the departure from Egypt, and the dividing of the Reed Sea; they trembled and feared, and fled from their place, as it is said, "The peoples have heard, they tremble" (Ex. 15:14).