To illustrate, let us imagine that we here on earth desire to reach the moon. That is a definitive goal which we can see. We can measure the distance and make plans to reach the moon. To us here on earth that is the ultimate in space exploration. Now let us imagine that one day we reach the moon. Just as we become acclimated to this enormous triumph, our eyes turn upward yet again and we see the vast expanse of space, the innumerable stars, planets, and galaxies, stretched out before us for more than 15,000,000,000 light years, and enlarging its borders faster than we could ever hope to keep up. We will never get to the end of it.
This, in a nutshell, is what it is to find ourselves lost in the depths of Christ. The more we know of Him, the less we realize we know.