The "flesh" as used throughout this chapter refers not to our human bodies, but to the principle & power of sin. Sin is present & often operating in our body, not to be equaled with the body.
"Not guilty; let him go free"- what would those words mean to you if you were on death row? The fact is that the whole human race is on death row, justly condemned for repeatedly breaking God's holy Law. Without Jesus we would have no hope at all. But thank God! He has delivered us not guilty & has offered us freedom from sin & power to do his will.
The Spirit of life is the Holy Spirit. He was present at the creation of the world, & he is the power behind the rebirth of every Christian. He gives us the power we need to live the Christian life.
Jesus gave himself as a sacrifice for our sins. In Old Testament times, animal sacrifices were continually offered at the Temple. The sacrifices showed the Israelites the seriousness of sin: blood had to be shed before sins could be pardoned. But animal blood could not really remove sins. The sacrifices could only point to Jesus' sacrifice, which paid the penalty for all sins.
Daily we must consciously choose to center our lives lives on God. Use the Bible to discover God's guidelines, & then follow them. When the Holy Spirit points out what is right, do it eagerly.
A Christian is anyone who has the Spirit of God living in him. If you have sincerely trusted Christ for for your salvation & acknowledged him as Lord, then the Holy Spirit has come into your life, & you are a Christian. When the Holy Spirit is working within you, you will believe that Jesus Christ is God's Son & that eternal life comes through him; you will begin to act as Christ directs; you will find help in your daily problems & in your praying; you will be empowered to serve God & do his will; & you will become part of God's plan to build up his church.
The Holy Spirit is God's promise or guarantee of eternal life for those who believe in him. He is in us now by faith, & by faith we are certain to live with Christ forever.
Reference summary used from the Life Application KJV Bible, Tyndale House Publishers, Inc., Wheaton, Illinois