Rabbeinu Bechaye points out a small but important detail connected with קריעת ים סוף, the splitting of the Red Sea.
Hashem gives Moshe Rabbeinu a very specific command. He tells him, “ואתה הרם את מטך ונטה את ידך״, meaning that he was supposed to raise the staff, but stretch out his hand over the water, so that it would divide.
Moshe stretches his hand without the מטה, in order that the people not think that there was something magical about the staff. It was Moshe who was appointed by Hashem, to do all of these wonders.
This is why it says in the Torah and we add it in our daily morning prayers, ״ויאמינו בה׳ ובמשה עבדו״, that they believed in Hashem and in his servant, Moshe.