Rabbi Simon said: This is analogous to the holder of the rod [of office]6Roman lictors (magistrates) carried bundles of rods called fasces as a symbol of their office. who was walking outside with the rod in his hand. They said: ‘Were it not for the rod in his hand, he would not be respected.’ The king heard and said: ‘Put down the rod and go outside. Anyone who doesn’t greet you, I will remove his head.’
So, the Egyptians said: ‘Moses would have been unable to do anything but for the staff; with it he struck the Nile, with it he brought all the plagues.’ When Israel came into the midst of the sea and the Egyptians were standing behind them, the Holy One blessed be He said to Moses: ‘Cast away your staff, so they will not say: Were it not for the staff, he would not have been able to split the sea, as it is stated: “Raise your staff.”’ 7The midrash is commenting on the fact that Moses was commanded in Exodus 14:16: “And you, raise your staff, and extend your hand over the sea, and split it; and the children of Israel will come into the midst of the sea on dry land.”
However, in the description of the actual action, only Moses extending his arm is mentioned: “Moses extended his hand over the sea and the Lord moved the sea…” (Exodus 14:21).