One of the most incredible miracles of all times occurs, the Splitting of the Sea, and it’s conclusion happens the same way it began:
וַיֹּאמֶר ה אֶל מֹשֶׁה נְטֵה אֶת יָדְךָ עַל הַיָּם וְיָשֻׁבוּ הַמַּיִם עַל מִצְרַיִם עַל רִכְבּוֹ וְעַל פָּרָשָׁיו – Hashem said to Moshe; “Stretch your hand over the sea, and the water will crash back onto the Egyptians, their chariots, and their horseriders. (14:26)
R’ Shimshon Pinkus wonders why it was necessary for him to lift his hand to “close” the sea, as he did when it came to splitting it. The miracle would be over when the last Jew went ashore, and the sea returning to its normal natural state would seem to be something that just ought to “happen”.
R’ Shimshon Pinkus explains that Hashem was trying to teach the Jews an essential lesson about “natural” occurrences. Quite understandably, splitting the sea requires an action of some sort because it was a miracle; but the returning of the sea to its natural state is equally miraculous!
We take the laws of nature and physics for granted – Hashem was expressing that we ought not to. There is no fundamental reason which causes things to happen; it is all Hashem. This was the underlying message of Hashem’s command for Moshe to stretch out his hand, in the same way, to both start and conclude the miracle. They are the same from Hashem’s perspective.