"I beseech you therefore, brethren, by the mercies of God, that you present your bodies a living sacrifice, holy, acceptable to God, which is your reasonable service. 2 And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God." Romans 12:1-2
This is a reference to the commandment of God under the Law of Moses that sacrifices, and burnt offerings be brought to the priest to be offered up wholly and fully on the altar in worship of the Lord. All of the sacrifice offering would be burned on the Altar and the Aroma from the sacrifice would ascend to God as an odor of sweet aroma.
"...but he shall wash its entrails and its legs with water. And the priest shall burn all on the altar as a burnt sacrifice, an offering made by fire, a sweet aroma to the LORD. Leviticus 1:9
Getting our physical bodies in shape is a good and godly thing to do, especially after we have neglected to keep ourselves in a discipline of regular, balanced eating, exercise, and rest, particularly getting adequate amounts of sleep. All this can be a challenge. But it is not nearly as important for optimal health and over-all well-being as renewing our minds. Having a perfect physical appearance means little if we are trying to navigate this life with an un-renewed mind.
"...present your bodies a living sacrifice…And do not be conformed to this world but be transformed by the renewing of your mind Romans 12:1-2
Before we were born again by the Spirit of God, we operated in the world driven by the dictates of our old thoughts, old habits, old passions, and base desires. Our appetites were controlled by whatever satisfied our hunger for pleasure in the moment, regardless of how fleeting and unfulfilling those pleasures might have been.
The momentary desire to satisfy our baser instincts drove us to ever-worsening health, deeper debt, more pain and discomfort, and the progressive loss of our ability to choose what was profitable for us instead of giving-in to the constant borage of lies, doubts and fears directed at us by the devil.
But now, as the children of God, born again from above, by the Spirit of God, we are no longer bound to those old lies, doubts, and fears. We are new creations with new minds capable of resisting the devil, such that he will flee from us. Now, being free to exercise the authority we have from God and the power of the Holy Spirit working in us, WE CAN DO ALL THINGS THAT ARE PROFITABLE FOR US. WE CAN KEEP OURSELVES FROM GIVING INTO THE MENTAL AND EMOTIONAL PRESSURES TO CONFORM TO THIS WORLD. By the Spirit of God at work in us we are being transformed into the image of Christ.
Though we might momentarily stumble along the way, or experience TEMPORARY setbacks, we have no reason to give up or be dismayed, disappointed or even for the slightest moment, entertain any thought of failure.
YOU HAVE NOT FAILED!!! GET UP AND GET BACK IN THE RACE!!!
We are not running to run! We are running to win, because our Champion, Jesus Christ Our Lord, who now lives in us, has already won the race for us.