Water, water, everywhere, but not a drop to drink. Oh, did we say water? We meant blood. Well, bloody water. Okay, let's just dive in. (To the text! Don't be gross.)
If you knew one thing about Moses before reading Exodus, it was probably that he was put in a basket in the Nile as a baby. But why do we focus so much on that?
The Nile River was the source of life for ancient Egypt and a main player in its development as a culture. The Nile = irrigation. Irrigation = farming can be done by a few people, instead of a zillion. Fewer people farming = more room for a bustling civilization.
So Moses floats along the river until he's found by Pharaoh's daughter. Normally, class movement like this would be unheard of—unwanted baby to prince!—but the river makes it possible. The motion of the current reflects the motion of the civilization. Up, up, and away.
Humans need water. Case closed. But what about gods?
Well, water was a huge proving ground for ancient gods. Basically, to be anyone in the divine pantheon, you had to prove yourself against the water and the creatures that lurked within it. Having control over water was huge in a farming society. And having control over oceans—these vast bodies of water—well that's just nuts.
God uses water for his own purposes on several occasions: he gets the Israelites through the Red Sea, makes salt water sweet (15:25), and helps Moses release water from a rock (17:5-7). The Red Sea is particularly important because God uses his control over water to save his people. And kill the enemies.
As a bonus, God is even described in sea-monster fashion: "At the blast of your nostrils the waters piled up, the floods stood up in a heap; the deeps congealed in the heart of the sea." (15.8). God wins, ocean loses, Israelites survive.
But what exactly did God do? Our modern interpretations suggest that the waters parted, but a closer look at the text reveals other possibilities. Chapter 15:1-19, a super-old part of Exodus, water is a means for destroying the Egyptians, but there is no mention of a "parting" of waters:
We can definitely picture walls of water, but the takeaway is that water is a source of power for God and that he has total control over the elements. If making it swallow up the Egyptians wasn't proof enough, how about when he grants Moses the ability to turn the water of the Nile into bloody torrents?
One last thing. A lot of people reading the Bible associate water with baptism. But it was being used as a symbol of purification long before John the Baptist came on the scene:
The Lord spoke to Moses: You shall make a bronze basin with a bronze stand for washing. You shall put it between the tent of meeting and the altar, and you shall put water in it; with the water Aaron and his sons shall wash their hands and their feet. When they go into the tent of meeting, or when they come near the altar to minister, to make an offering by fire to the Lord, they shall wash with water, so that they may not die. They shall wash their hands and their feet, so that they may not die: it shall be a perpetual ordinance for them, for him and for his descendants throughout their generations. (30:17-21)
Bottom line: water is everything. It's life, it's power, it's purity. Don't leave home without it.