Think of God’s mercy, my brothers, and worship him, I beg you, in a way that is worthy of thinking beings, by offering your living bodies as a holy sacrifice, truly pleasing to God. Do not model yourselves on the behaviour of the world around you, but let your behaviour change, modelled by your new mind. This is the only way to discover the will of God and know what is good, what it is that God wants, what is the perfect thing to do.
The sentence that leapt out at me in that was this:
Do not model yourselves on the behaviour of the world around you, but let your behaviour change, modelled by your new mind.
Romans 12 is often presented as setting out an ethics of gratitude: reformed behaviour as our grateful response to the promises of the gospel set out in the preceding eleven chapters. However, I think it goes deeper than that. Rather than just setting out a dynamic of “remember what God has done and then demonstrate your gratitude”, St Paul is showing his profound understanding of the mimetic nature of human desire and behaviour.
Our default setting is to “model [ourselves] on the behaviour of the world around [us]”, desiring according to the desire of the other, leading to mimetic rivalry and conflict. To “think of God’s mercy” is not merely to give ourselves an object lesson in why we ought consciously to behave better, but to establish an alternative model for our desire, even our unconscious desire: the model of Christ Jesus (to use Paul’s favourite title) in his life, death and resurrection.
Because human nature is mimetic, so is human understanding: we understand things better when we have a model to imitate, rather than just abstract propositions to absorb intellectually. Hence it is only by establishing that new model for our desire, the model of Christ’s non-rivalrous love for us, that we can understand the truths which that model reveals. Hence:
This is the only way to discover the will of God and know what is good, what it is that God wants, what is the perfect thing to do.