Because Christ is in us, our spirit is life. Regeneration is a mingling work to mingle Christ with our spirit. Today Christ is life, and our spirit is also life. This is because our spirit has been made one with Christ, who is life. First Corinthians 6:17 says, "He who is joined to the Lord is one spirit." Surely this one spirit comprises both Christ and our spirit, so both Christ and our spirit today are life. This is why we need to exercise our spirit. If we exercise our spirit, life will be infused into people because our spirit is life. If we exercise our spirit to minister to others, then our spirit will reach others as life.
Romans 8:6 says that the mind set on the spirit is life. Not only our spirit is life; even our mind can be life. But this mind must be set upon the spirit. This means that this mind must be flooded, saturated, and infused with the spirit to become the mind of the spirit. Eventually, the spirit becomes the spirit of our mind. This is mentioned in Ephesians 4:23. Because our mind is set upon the spirit, our spirit saturates our mind and makes our mind a mind of the spirit. Eventually, our spirit becomes the spirit of our mind. The renewing is by this spirit that saturates our mind. We always have to tell the saints this spirit is the mingled spirit. It is our spirit mingled with Christ as the life-giving Spirit.
Because our mind is one with our spirit, connected, joined, saturated, and infused with our spirit, our mind is also life. Such a mind can function to minister life to others. By our natural mind we cannot minister life to others. This mind is not life. But when our mind is joined to our spirit and is saturated with our spirit that is life, our mind at this time also becomes life.
For this point we have to say that the mind set on the spirit means the mind is joined to the spirit and is relying on the spirit. The spirit can be likened to the husband and the mind to the wife. The mind as the wife should always rely upon the spirit as the husband. The mind should always depend upon the spirit. Just as the wife and the husband are really one couple, the mind and the spirit are really one unit. They are no longer separated.
Romans 1:28 speaks of the fallen mind as a disapproved mind, a reprobate mind. A reprobate mind is one that rejects God and that is rejected by God. It is a mind that disapproves of knowing God and is also disapproved by God. That was our original mind in its fallen state.
Romans 7 shows us that a saved person seeking to serve God uses his natural mind to keep the law and is defeated (vv. 23, 25). In chapter seven the mind is no longer reprobate, but it is still independent. It is living like a widow, having the heart and desire to do things but without a husband to rely upon. The mind in chapter one is a reprobate one, but the mind in chapter seven is a seeking one, seeking after God and trying to please God but not relying upon the spirit.
Romans 8 also mentions the mind, but the mind here is set upon the spirit. Now the mind as the widow has married a new husband. It is not just a seeking mind but a married mind, a mind married to the spirit. Such a mind becomes one with the spirit, and because of this, such a mind also becomes life. The fourth place which talks about the mind in Romans is 12:2, which speaks of the renewing of the mind. Such a relying mind must be renewed. Thus, in Romans we see the reprobate mind, the seeking mind, the relying mind, and eventually the renewed mind. In order for us to have a renewed mind we need the mind relying on, depending upon, the spirit.