The story so far: Joshua and the Israelites have scouted out the land of Canaan and are preparing their invasion, according to God's decree. And then God says "you should definitely get yourselves prepared, because tomorrow I'm handing them over to you - don't screw it up." And this is where we join the story ...
Joshua said to the Israelites, "Come here and listen to the words of the LORD your God. This is how you will know that the living God is among you and that he will certainly drive out before you the Canaanites [and everyone else]. See, the ark of the covenant of the Lord of all the earth will go into the Jordan ahead of you. Now then, choose twelve men from the tribes of Israel, one from each tribe. And as soon as the priests who carry the ark of the LORD - the Lord of all the earth - set foot in the Jordan, its waters flowing downstream will be cut off and stand up in a heap."
So when the people broke camp to cross the Jordan, the priests carrying the ark of the covenant went ahead of them. Now the Jordan is at flood stage all during harvest. Yet as soon as the priests who carried the ark reached the Jordan and their feet touched the water's edge, the water from upstream stopped flowing. It piled up in a heap a great distance away, at a town called Adam in the vicinity of Zarethan, while the water flowing down to the Sea of the Arabah (the Salt Sea) was completely cut off. So the people crossed over opposite Jericho. The priests who carried the ark of the covenant of the LORD stood firm on dry ground in the middle of the Jordan, while all Israel passed by until the whole nation had completed the crossing on dry ground. (Joshua 3:9-17)
To tell you the truth, a friend referred me to this passage because he thought it was cool how the river behaves here. I find it interesting too. See, the river washes all the way back to a town called "Adam." Curious, I remember a guy named "Adam" - screwed up something big, if I recall. And the salt sea was a place of death, the end of all things, etc - and the water doesn't get to there. So we have this stretch of land covered in water (under which lots of things could drown - namely the people wading around in it), and as soon as the Ark of the Covenant enters the water (in the middle of the river) with twelve faithful guys, all that water gets pushed back to both ends - Adam to the end.
It doesn't take a genious to recognize that it's a pretty symbolic event. The Ark is a symbol of God; God chose the Ark to use as a representation of His covenant on Earth. And so God's covenant enters the river - a place of certain death for people in it - and the water gets moved away.
Ok, I'm going to stop beating around the bush - the water in the river is sin. The Ark is Jesus, and it enters the middle of the river - in the middle of history. Funny, isn't it? Jesus came in the middle of history and suddenly the waters of sin and death are moved all the way back to Adam and stopped flowing all the way to the very end of the river - to the end of time.
If that's not an illustration of God's grace towards humanity, then I'm reading the wrong book. And so I'd think this is a fairly interesting way of talking about Calvinism - again, it's not about a select few, it's about all of humanity.