Give life to your mortal bodies ...
you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. But if anyone does not have the Spirit of Christ, he does not belong to Him. If Christ is in you, though the body is dead because of sin, yet the spirit is alive because of righteousness. But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ Jesus from the dead will also give life to your mortal bodies through His Spirit who dwells in you. So then, brethren, we are under obligation, not to the flesh, to live according to the flesh — for if you are living according to the flesh, you must die; but if by the Spirit you are putting to death the deeds of the body, you will live. For all who are being led by the Spirit of God, these are sons of God. -Romans 8:9-15 NLT
There is a practical mysticism woven in this passage as Paul speaks of the way that Christ gives life to our mortality. Before we were born spiritually (i.e. born again) we lived without a compass and were spiritually weak. This radically changed when the Holy Spirit came and gave us new hearts. No longer would we be spiritually and morally adrift. We experienced a new power when the Holy Spirit came into our lives. We are no longer alone when we are tempted.
The issue for us is now one of strength and power. Will we follow the Spirit's lead and do the things that strengthens our heart or will we follow the rationalizations of our brain and continue to strengthen our flesh? I liken it to preparing for a battle. Each time we follow our innermost being we pump spiritual iron. Every time we love an enemy we cause power to flow to our hearts. When we pray and embrace the scriptures we do the things that give life to our mortality.
Teach us Lord to do the things that strengthen our innermost being and give life to our mortal bodies.