“But some things just come naturally….that’s just in his nature.” No. Plain and simple. No.
Human nature is already claimed, and what comes naturally may indeed be other than Christ and His life, but this is no longer what’s natural to us. What’s natural to us is the life that Jesus makes possible. The future and purpose of nature is Jesus Christ Himself. When we think of what’s natural, we as Christians don’t begin what the world thinks is natural. The natural has been revealed to us as that which comes from the end, the Kingdom, wherein God’s reign is full. We as the Church are the community where the laws of new creation are normative for our life and practice._
Being the church, we must learn that nature has been redefined for us around and in Jesus. We don’t begin to think about what comes naturally apart from Jesus. He commands the center of everything we think and say. God has ideas about nature, and they are presented to us rather clearly, and we have to think in and with God’s revelation.
God’s idea of nature is Jesus. What comes naturally, is that Kingdom, and its laws, not this one. What comes naturally is recovered on the basis of the gospel. “The Natural is that which after the fall is directed towards the coming of Christ”. 
What matters here is that Bonhoeffer is telling us that Jesus isn’t just something cute that happened once upon a time, He reorients all of human nature towards Himself, and whatever deviates from this is no longer natural, but unnatural. It is unnatural to oppose the coming of Christ.
It is incumbent upon us to learn to think this way about the world, or else we will fail to have the imaginative power that the gospel demands of our communities. We know the end of the story, we know that in the end, God will set all things to rights, and that justice will pour out over all creation. We know that God’s good creation was never intended to be as we see it now. That’s what Jesus means. Jesus is God’s idea of what creation is and means, because God Himself enters creation and lives the life of a creature always disposed to God in the right manner.
We think in and with the end of the story, because that’s what God intended, and intends for everything. Someday everything in all creation will look and think and act like Jesus, this is not to say we stop becoming individuals. What will happen is that just as Jesus is infilled with the presence of God so too we will be. Just as the sacraments are filled with His presence so too, each of us in our unique subjectivity will refract the manifold and unlimitedly creative power of the Triune God. We will all be sacraments, all creation will indeed in the end be sacramental. If you wonder what new creation looks like, look at the table of communion.
What comes naturally is the redeemed world we hope for. That’s what has always been intended. What’s in our nature as Christians is not us, but Christ. He is the goal of creation, and in Him we will be more and more truly ourselves.