Please. The Red Sea was parted to make a point as much as safe passage. I think this God can make his will known without the say-so & stamp of approval from some old fogies.
Those "old fogies" just somehow miraculously happened to be the ones capable of accurately preserving those statements for millennia. How many civilisations on Earth have even lasted that long, let alone tested and approved prophetic documents?
Would you prefer that God strictly speak through plagues, partings and major events, while you try to decipher what he wants from them?
The red sea story could be said to foreshadow Christ, so could all the hebrew feasts, but none were so direct a prophecy as Isaiah gave. It also makes the point that one person, plus God, can change all of history to follow.