Justin Taylor has a great analogy on his blog today.
"Picture the river as redemptive history flowing toward the ocean which is the final kingdom of God, full of glory and righteousness and peace. At the end of the river the ocean presses up into the river with its salt water. Therefore, at the mouth of the river there is a mingling of fresh water and salt water. One might say that the kingdom of God has pressed its way back up into the river of time a short way."
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