Ephesians 3:19 and to know the love of Christ which surpasses knowledge, that you may be filled up with all the fulness of God.
Here's an excerpt from another prayer, this time the Apostle Paul's. In verse 16 he prays that the Ephesians would be strengthened so that in verse 17 Christ can live in their hearts and in verse 18 they can be able comprehend the magnitude of God. Then by verse 19 he talks about being able to know the love of Christ that surpasses knowledge so that they can be filled with all the fullness of God.
A preacher I listen to once said that a person could write "this is possible" in the margin of their Bible next to verse 19. And I have done that ever since.
Paul wouldn't tell us that we could aspire to know the love of Christ which surpasses knowledge if it weren't possible. It is possible if you refer back to verse 16 and know that we can be strengthened to get to this point.
Paul wouldn't tell us that we may be filled up to all the fulness of God if it weren't possible. Again we must refer back to the previous verses and understand that we need "to be strengthened with power though His Spirit in the inner man" (from Ephesians 3:16). And we get this strengthening "according to the riches of His glory".
Just like Moses prayed, "If I have found favor in Thy sight, let me know Thy ways that I may find favor."
May God grant us strength in the inner man by the riches of his glory, so that Christ can live in our hearts and that we can actually know a love that is beyond our natural ability to know, and contain the fulness of God within ourselves.