Spirit is Rebirth
Firstly, it is our spirit that is rebirth. In our spirit dwells God's Holy Spirit. We are 100% righteous, complete in Christ. Col 2:10; 2Pet 1:3, Eph 3:20. Within us, we have God's faith, grace, power, wisdom, etc... everything we need for life and godliness. Then what is missing? Why do some Christians still live a defeated life ? The answer lies in the following.
Mind to be Renewed with the Word.
Secondly, and however, our mind remains the same - before and after our salvation. Our defective thinking that causes us to have so much problems remain unchanged. Unless we change our thinking and thought patterns, we will remain in our failures even though we are saved. Our mind therefore needs to be renewed with the Word of God. Rom 12:2. We need to know the new identity and resources that we have in Christ. These are told in the Bible.
Body to be Under Controlled of Spirit through the Mind
Thirdly, our body remains the same. We may feel better because of the joy of salvation. But unless we get our mind renewed and then exert influence on our body, our body remains the same... weak or sick as before.
Until we know the New Life and commit to live accordingly we cannot experience the abundant life for which Jesus Christ died to give us.
No Need to Ask for More but to Live it Out in Faith.
We are to live out this new life in our spirit Phi 2:12-13 letting our soul be motivated from the inside and controlling the body to work out the glory of God. Christian growth is about knowing our identity in Christ and working out our soul and body to conform to the image of Christ. People in the world do not see our spirit or read our mind except through our body - what we say and how we act.
For salvation of man, see Salvation of Tripartite Man - The Details.