There was one man, Nachshon Ben Aminodov, who just went ahead and did what he thought was the right thing. He jumped right into the water.
He was thinking: - "G-d said we came out of Egypt to receive the Torah on Mount Sinai - then that is exactly where we are supposed to go," thought Nachshon. "Going back to Egypt or even praying to G-d will not bring us closer to Mount Sinai. Forward towards Mount Sinai is the right direction, and that's where I'm going!
There is water in the way? No matter - it's the right direction and will bring me one step closer to Mount Sinai, where G-d wants me to be."
Nachshon didn't know that a miracle would occur and the water would split. And it actually didn't even split right away. The water was knee deep, but he went on. The water reached his thighs, but he kept moving. The water came right up to his neck, but he didn't turn back. Then, all at once, the waters split and he found himself on dry land.
Now, how was he sure that it was right to plunge into the sea? He wasn't sure. But he just knew ONE thing : He knew what G-d had told the Jewish People.
We have been given the promise: "The time of your Redemption has arrived." We know where we're going and we are pushing on in that direction. Even if it seems that some things are blocking our way, we're following Nachshon's example and heading straight towards redemption, regardless of the obstacles.