Sometimes, a person can struggle to reconcile grace and freedom from the law with any type of bodily discipline being encouraged and advised under the New Covenant.  They struggle to imagine that any suggestion to bring their body under subjection to truth could be anything other than a call to performance or a mixture of legalism.

Is it possible to find an apostle in the Bible better versed in grace than Paul?

When anyone knows the Scriptures and what they teach regarding grace, they know that the letters Paul wrote contain most of the instruction in the truth concerning grace.  Paul is often known as the grace apostle.

So, we know Paul was not a minister of mixture.  He testifies that his ministry is of the New Covenant.  He also declared he did not handle the word deceitfully.

2Corinthians 3:5 Not that we are sufficient of ourselves to think of anything as being from ourselves, but our sufficiency is from God, 6 who also made us sufficient as ministers of the new covenant, not of the letter but of the Spirit; for the letter kills, but the Spirit gives life.

2Corinthians 4:2 But we have renounced the hidden things of shame, not walking in craftiness nor handling the word of God deceitfully, but by manifestation of the truth commending ourselves to every man’s conscience in the sight of God.

Paul was adamantly against any type of mixture in ministry concerning the gospel of grace.  But even still, he found it appropriate and necessary to address matters about the discipline of the body.  Unlike the gnostics who believed nothing done in the body mattered because they taught that only that which was of spirit mattered.  Paul believed the body had significance because it was God’s temple.

1Corinthians 6:18 Flee sexual immorality. Every sin that a man does is outside the body, but he who commits sexual immorality sins against his own body. 19 Or do you not know that your body is the temple of the Holy Spirit who is in you, whom you have from God, and you are not your own? 20 For you were bought at a price; therefore glorify God in your body and in your spirit, which are God’s.

Our bodies still matter to God.  God cares about these bodies of ours for a reason.  I would assume that you care about the condition of your home or apartment.  You do not want it infested with rats, roaches, or some other nuisance pest.  You wouldn’t want a drifter squatter to come in and call it home and mess it all up.  You wouldn’t want it to leak water over your bed at night during a storm.  You would want it to be a nice place for you to live.  You would want it to be pleasant, inviting, clean, and have things in it you can appreciate and enjoy.  That is pretty much what is being conveyed by what Paul says regarding the body.

“Therefore, glorify God in your body and spirit, which are God’s.”  God lives in us.  That is a very important truth.  Our bodies are the temple of the Holy Spirit who lives in us.  We are not our own.  Therefore!  That is an important word to pay attention to.  This emphasis on body and spirit is meant to help us be aware of how important it is to be mindful of being His temple and glorifying Him both in body and spirit.  There’s great wisdom in “Therefore” instruction.