When we talk about eternity being the place from which we come, though we have never known it (just as Israel came from Canaan, but had only heard whispers of it from their distant ancestors), we create a bit of confusion that we must clear up.
There's a common preaching in certain Christian circles that this means that we have always existed. This is only further complicated by the understanding that we have that from the very beginning, God imagined us. He created us in His mind as part of this cosmic plan He has that bends toward eternity. So from the very "in the beginning," there was you.
Except there wasn't.
The problem with this teaching is that it makes us eternal beings, having always existed. This makes us very much like God. Too much like God, really. It puts us on a level playing field - hey, if God was there on the first day, and so were we, then what's so special about His eternal nature? It's not any different from my own. And if I am not so very different from God, it's just a short jump until He is created in my image and not me in His (which is exactly what we've done, by the way).
So we have to start to understand that the fact that we have always been in God's mind and always in God's story does not mean that we have always existed. A few years ago, there was this drawing that I had in my mind (actually, there's another one now), but I hadn't yet put it on paper. It existed as an idea, even as an idea that I loved deeply, but I could not have hung it on the refrigerator. Thus, it did not truly yet exist.
The same is true about us. We have existed from the very beginning as someone that God has loved, but until the moment that He knit us together in our mother's womb, we could not have stepped onto the stage of eternity at all. We are not eternal beings.
Think back to the creation story in Genesis. God was building this entire galaxy in order that one small garden might become home to Adam, the apex of His creation. The ultimate end of His creative work. The "very good" in a world that was only "good" without man. But when the first five days were done, God did not simply pull Adam out of a closet or pluck him out of some eternal void and put Him on the earth; until God bent down into the dirt and formed a man and breathed the very breath of life from His own lungs in him, Adam did not exist.
Adam was never eternal. And if Adam was never eternal, you can bet your sweet biscuits that you're not, either.
Yet, we talk about eternity as the place from which we came. Our hearts echo with memories of it. Shadows of its light dance behind our eyes. There's something in us that just knows eternity, though we have only ever heard of it. How is that even possible if we did not come from there? If we are not eternal beings who have simply stepped into time?
It is possible for us the same way it is possible for Israel - it is the story that has been passed down for generations, God's very story woven into our time. It comes from the very first breath God breathed into us, for His breath is eternal and always has been, and it brings into the depths of our souls echoes of that from which (and for which) we were created.