In the external order we look to certain persons and things to provide the same security. It can be money, position and all the comfortable security that they provide. Perhaps more restraining, yet seemingly securing, is the adoption of certain roles which each of us plays and expects those who relate to us to play. There is a certainty and security if I can name who someone is, who I am, and then live a related life in terms of those roles. There is no risk or uncertainty in terms of the future, and a comfortable sense of security is achieved.
Grace does build on nature.
Our life in God is incarnate. In the same way in which we seek the security of internal and external mastered patterns in our natural living, we can seek them in our spiritual life, and most probably will. I will concede that there are those who go through radical conversions which seem to change both the natural and supernatural ordering of their lives. But for most of us our faith and the living of the Christian life have grown side by side with our natural maturing process and been ultimately affected by it. We need to break out.