Sforno on Exodus 14:8/ספורנו על שמות י״ד:ח׳

1ובני ישראל יוצאים ביד רמה, the meaning of the word רמה here is similar to the meaning of the same word in Deuteronomy 32,27 ידינו רמה, where it means: “our own hand has prevailed.” At the time of their departure they had been confident of their ability to defeat Pharaoh and his military machine as they were much stronger in numbers. The verse teaches that they were relying on their numbers instead of considering their total lack of experience in the art of war. They would have had every reason to fear the numerically inferior Egyptians who had all this experience going for them.