In 2 Cor. 5:17 the apostle Paul defines the new creation as being in Christ. This does not mean, of course, being physically. In the previous verse Paul writes that "we regard no one according to the flesh", so the body element is not important here. And this is interesting information because even 95 percent of human behavior is controlled by the subconscious mind - by how the neurons in our body work and are connected. We are talking about a control that is in some sense mechanical, independent of consciousness. Meanwhile, the apostle states that from the point of view of the new creation it does not matter. What does matter is the remaining 5 percent. Not because it has such a direct impact on our behavior (because, as you can see, it does not), but because it can change - shape anew - the remaining 95 percent. The way we shape our thinking will shape our subconscious and then our behavior.
Because Paul points out the time element in 2 Cor. 5:16 - "from now on, we regard no one according to the flesh" (NKJV) - it is worth going back a little further to see which moment is this definitional beginning of the new creation. 2 Cor. 5:14,15 - "For the love of Christ compels us ... that those who live should live no longer for themselves, but for Him who died for them and rose again" (NKJV). The new creation, therefore, begins where the 'love of Christ' is at work, which literally 'compels' its possessors to live for Christ. In order to live for Christ, one must also know why he gave his life: "For this cause I was born, and for this cause I have come into the world, that I should bear witness to the truth" (Jn. 18:37 NKJV). Our Lord refers to this element when, as he is about to go away, he commands to make disciples of the nations and teach them to obey all that he has taught (Mt. 28:19,20). Here, too, the basic element is the truth, knowing it and living in accordance with it.
Since God is a God of order, also the reality created by him is governed by certain rules, has a specific structure (1 Cor. 14:33). Moving in accordance with God's laws brings peace, disobeying them brings misfortune and death. The man of God is to follow this structure, but first he must know it. This knowledge, however, has not been given to us a priori, it is something we must strive for; it is a process of constantly learning as our Lord says in Jn. 17:3. However, we do not have direct access to this metaphysical reality, therefore God gives elect two things: his Word, which informs about this reality, and his spirit - the spirit of the 'love of Christ', which is also called the love of truth in the Bible (Rom. 5:5; 2 Thess. 2:10). The task of the love of truth is to motivate and empower the elect to get to know this extra-material structure; God's Word shows what it looks like.
The effect of this cognition process will be first to shape our consciousness according to the understanding of the structure of truth, and then also to shape our subconscious into patterns of behavior in accordance with God's law. The reformed consciousness and the subconscious are in turn what the Bible calls the 'new man'. In Eph. 4:20-24 the apostle Paul describes this process exactly: verse 22 - we are to put off the 'old man' (the way we think and act as we used to); verse 23 - the means to achieve this goal is to 'renew the spirit of your mind', that is, to think according to the truth; verse 24 - learning the truth will allow one to put on the 'new man' - reforming the subconscious mechanisms of behavior. The condition for this change is a change of thinking, and this is how the Scriptures present it - the condition for putting on the new man is putting on the new creation.
The application of the term 'new creation' to consciousness seems to be justified above all by the immediate context of 2 Cor. 5:17. In the introduction to the commentary, I noted that Paul excludes the concept of the body in relation to the new creation, while the subconscious is encoded in our body, in our nervous system. The love of truth does not work in the subconscious but in consciousness, leading to active (and conscious) development in knowledge. The New Testament in many places alludes to this conscious activity, including the already mentioned Eph. 4:23 and 2 Tim. 1:7, where we read about the 'spirit of the sound mind' and the 'spirit of power and of love' (NKJV). The apostle John says that "the Son of God has come and has given us an understanding" (1 Jn. 5:20 NKJV), Paul in turn writes about 'reasonable service' (Rom. 12:1 NKJV). Development in truth is an activity that is not automatic, but requires work on the part of the called.
However, doing this work is essential. It is not only knowledge of individual doctrines, but also - and above all - the ability to distinguish between what is beautiful and what is bad (Heb. 5:11-14). It is not just knowledge, but knowledge derived from skills. Thanks to it, we can not only act in known situations (this is where the subconscious works by using developed response strategies), but also unknown - new situations that require analysis and decisions. Analysis and decision, on the other hand, require understanding - knowledge of the rules that govern our reality. This kind of maturity is the most precious thing a believer can earn in himself and the most precious gift we can receive from God (Phil. 2:12,13).