Midrash Sefer, “Beshalach”: The Lord commanded Moses to spread his arms above the sea, and a light eastern wind began to blow. In the meantime, the children of Israel went on their way during the whole night, and thus came closer and closer to the seashore.
The Egyptians followed them, but did not succeed in conquering the camp. They shot arrows and threw stones at the Jews, but the cloud of the Creator absorbed everything.
It was the same cloud that usually moved before the children of Israel during the day. That night, instead of disappearing in the dark as it usually did, it moved behind the camp in order to absorb everything that was shot and thrown by the Egyptians. Moreover, the Creator’s angels flew behind the Jews in order to protect them.
There is a law of equivalence of form: If you move toward unity and dissemination, toward developing your spiritual attributes, you are connected to the Creator to some extent in regard to that. Although you are not in contact with Him, there is a connection in the form of a cloud, in the form of help from behind and before. This means that the Surrounding Light operates on you.
A cloud is the Surrounding Light that, on the one hand, is invisible and concealed, but on the other hand, is revealed in its actions like a magician who suddenly appears to hold something in his hand without any evident reason. This means that half of the actions are concealed and half of the actions are revealed. At the same time, the outcome is revealed while the reason is beyond the Machsom (barrier).
From KabTV’s “Secrets of the Eternal Book” 4/30/14