Considering Paul's background, it is hardly surprising to see him trying to come to grips with how God's promise given specifically to Israel might also extend to the Gentiles.   I don't think that we see the same problem ourselves or think that it is as important as Paul does: I believe that we are more intrigued by the underlying thought that God shows any favoritism at all.

Why did God choose to give a unique combination of gifts to each of us and to apparently show some of us greater favor?  It would be foolish for us to think that we could explain God's ideas about anything with any accuracy or exactitude, but I suspect that the answer is at the root of our identity and the relationship with God which that identity makes possible.

God invites each of us to come to him by a separate and personal path, and each of us must make that journey in some solitude.  No one can live our lives for us, learn our lessons or undergo our trials, and so we each must take personal responsibility not only for responding to God's love by the way that we live our lives, we must also accept the dignity that God offers us with it.  We do in fact live lives similar to those of others, and we live them in the community of the Church and ultimately in the mystical Body, but the mysterious balance between our finity and God's endless immensities, between our aloneness and the call to bliss in living with God's own life --- it will take all of our time on earth to discover just what God's promise is to each of us and what our response is, to find out what our talents and our weaknesses mean in terms of that relationship.

Our differences, our gifts and shortcomings and the little glimpses of truth that each of us have make us like pieces of a picture puzzle.  It is what we are able to offer others and to receive from them which make us part of the whole, bind us together, and show the greater truth that is God's love for us.  And it is only when we are all united in the Mystical Body that the role of each of us, in all the many ways that we are gifted, will be revealed --- to the glory of God.