2 Corinthians 11:16-33, 12:1-11
"It is like a small child going to its father and saying, 'Daddy, give me sixpence to buy you a birthday present.' Of course, the father does, and he is pleased with the child's present. It is all very nice and proper, but only an idiot would think that the father is sixpence to the good on the transaction."
The fact is, as Lewis makes the point, everything we have is given from God. How can we boast of what we have received?
But, Paul continues to explain that the strength of Jesus is illustrated best in our weakness. So, when we are compelled by our own need to turn to Christ, we then end up with more strength than we would have had, had we not been deficient to start with. This too can be illustrated with C. S. Lewis' anecdote of the six pennies, for the boy now is six pennies and/or a gift for his Father richer in the deal. That is all we have to boast of, the pleasure in sharing the gift, is it not?!