The complete human personality (soul) consists of the spirit (mind, new creation) and the body (character). Both of these 'systems' are used to decide what to do in a particular situation. When there is a need to decide how to behave, the mind responds by analyzing information, projecting various scenarios, and reaching for knowledge that can be used in this particular situation, both to the past and the future. The character, on the other hand, is a 'fast response path', action-reaction. Because the character has pre-programmed ways of reacting in specific situations, by definition it results in repeatability - we know that if 'this' happens, then people A, B and C will react in this way (so we can say that we know their character). Research shows that character is responsible for behavior in up to 95 per cent of cases, i.e. 95 per cent of what we do results from a behavioral script. The remaining 5 per cent are cases that require analysis of the mind. However, because the mind is time- and energy-consuming, we reserve it for special, less-recognized life situations.
Defining character as the body in the Bible draws attention to the fact that the behavioral algorithms that we run automatically in certain life circumstances are stored in the body, i.e. in the nervous system. However, this raises a problem that the New Testament raises, namely these ready behavioral patterns are not always in line with Bible principles. Hence readers of the Bible will associate the concept of the body or 'bodily thinking' with sin, as a cause of transgression of the law. The guiding idea of the New Testament is our justification, i.e. the real reform of human personality (both in the element of mind and character) to God's standards of justice. The measure of perfection that has been presented to us that we may follow it is Jesus Christ. So, if we change our mind (mindset) in the image of Christ, the New Testament speaks of the 'mind of Christ'; if we change character ('body' according to Biblical terminology), the New Testament speaks of the Body of Christ. We become, therefore, the Body of Christ when we change character in the image of the Lord's character.
The Bible says that we are members of the Body of Christ and that Christ is in us. This is the same information, only the viewpoint is different. Being a member of Christ underlines the universal pattern of Jesus Christ and our 'fitting in'. If Christ is in me, it means that the principles represented in his mind and character are developed in my personality. We become members of the Body of Christ through baptism in the spirit - a concept which, in the context of the body, refers to the 'immersion' of the whole person (complete personality in every aspect) into the Lord's spirit. Because this process of 'immersion' (reform of the character according to God's principles) begins at the time of conversion symbolized by water baptism, membership in the Body of Christ belongs to all believers (elect and non-elect) who believe in Jesus Christ not only in theory but in practice, respecting the rules of conduct demonstrated by the Lord.