To give you a sample of what he says there:
“Do not be conformed to this world but be transformed by the renewal of your mind, that you may prove what is the will of God…” (12: 2). The two decisive words of this verse are “transformed” and “renewal”. We must become new people, transformed into a new mode of existence. The world is always in search of novelty because, rightly, it is always dissatisfied with concrete reality. Paul tells us: the world cannot be renewed without new people. Only if there are new people will there also be a new world, a renewed and better world. In the beginning is the renewal of the human being. This subsequently applies to every individual. Only if we ourselves become new does the world become new. This also means that it is not enough to adapt to the current situation. The Apostle exhorts us to non-conformism. In our Letter he says: we should not submit to the logic of our time. We shall return to this point, reflecting on the second text on which I wish to meditate with you this evening. The Apostle’s “no” is clear and also convincing for anyone who observes the “logic” of our world. But to become new how can this be done? Are we really capable of it? With his words on becoming new, Paul alludes to his own conversion: to his encounter with the Risen Christ, an encounter of which, in the Second Letter to the Corinthians he says: “if anyone is in Christ, he is in a new creation; the old has passed away, behold, the new has come” (5: 17). This encounter with Christ was so overwhelming for him that he said of it: “I… died…” (Gal 2: 19; cf. Rm 6). He became new, another, because he no longer lived for himself and by virtue of himself, but for Christ and in him. In the course of the years, however, he also saw that this process of renewal and transformation continues throughout life. We become new if we let ourselves be grasped and shaped by the new Man, Jesus Christ. He is the new Man par excellence. In him the new human existence became reality and we can truly become new if we deliver ourselves into his hands and let ourselves be moulded by him.
Paul makes this process of “recasting” even clearer by saying that we become new if we transform our way of thinking. What has been introduced here with “way of thinking” is the Greek term “nous”. It is a complex word. It may be translated as “spirit”, “sentiments”, “reason”, and precisely, also by “way of thinking”. Thus our reason must become new. This surprises us. We might have expected instead that this would have concerned some attitude: what we should change in our behaviour. But no: renewal must go to the very core. Our way of looking at the world, of understanding reality all our thought must change from its foundations. The reasoning of the former person, the common way of thinking is usually directed to possession, well-being, influence, success, fame and so forth. Yet in this way its scope is too limited. Thus, in the final analysis, one’s “self” remains the centre of the world. We must learn to think more profoundly. St Paul tells us what this means in the second part of the sentence: it is necessary to learn to understand God’s will, so that it may shape our own will. This is in order that we ourselves may desire what God desires, because we recognize that what God wants is the beautiful and the good. It is therefore a question of a turning point in our fundamental spiritual orientation. God must enter into the horizon of our thought: what he wants and the way in which he conceived of the world and of me. We must learn to share in the thinking and the will of Jesus Christ. It is then that we will be new people in whom a new world emerges."