Midrash su Esodo 7:20

It says: And all the waters that were in the river were turned to blood (Exod. 7:20), but later the blood reverted back to water. Living flesh was turned into rancid flesh, and the dead were restored to life. The staff became a serpent, and the serpent was converted into a staff again. The sea was converted into dry land, and later the dry land became a sea once more. Likewise it says: That calleth for the waters of the sea, and poureth them out upon the face of the earth; the Lord is His name (Amos 5:8). Thus it is said: And God spoke all these words.

"[And God spoke] all these words, saying" (Exodus 20:1). That God does all at once; kills and gives life at once, harms and heals at once. [God hears the prayers of] a woman on the birthing stool, sailors and desert-walkers and those bound in jail, one in the east and one in the west and one in the north and one in the south, God hears all these at once. And so it says (Isaiah 45:7) "God forms light and creates darkness". Dust, like so, is turned to a person, and returned to dust, as it says (Amos 5:8) "And [God] turns deep darkness to dawn". What is to the morning? Like its beginning. In its beginning what does it say, (Exodus 7:20) "And all the waters in the Nile were turned to blood", and returned blood to water. Living flesh is turned to a corpse, and the corpse is returned to life. The staff is turned to a snake, and the snake is returned to a staff. The sea is turned to dry land, and the dry land is returned to sea, and so it says (Amos 5:8) (Amos 9:6) "Who calls to the waters of the sea [and pours them out upon the earth -- Whose name is the Lord]". And so it is written (Exodus 20:8) "Remember Shabbat to sanctify it", and says (Numbers 28:9) "And on the Shabbat day two yearling sheep". It says (Leviticus 18:16) "The nakedness of your brother's wife you shall not uncover", and (Deuteronomy 25:5) "When brothers dwell together [and one of them dies and leaves no son, the wife of the deceased shall not be married to a stranger, outside the family. Her husband’s brother shall unite with her: he shall take her as his wife and perform the levir’s duty]" and all say at once, it happened. "And God spoke all these words, saying." (Exodus 20:1).