2 Corinthians 3:1…
Unlike all other forms of life and ministry, Christian living and ministry is accompanied by a power which makes it sufficient in all things and for all things.
We speak of this so often because it is the equipping power of the Holy Spirit of God. Paul writes about it here, because it is the power he trusts to be at work in the church at Corinth. This is so important to him because he cannot be there physically, and he knows the words he has written to them in his letters have no power in and of themselves – but the Holy Spirit does.
It is not the letter of the Law of God which saves – but the power of the Holy Spirit working through it.
Paul points this out as he compares the Law of God in all its glory as given to Moses on Mount Sinai to the power of glory of the Holy Spirit working according the Law of God.
(We remember 3000 died on the very day Moses descended from the mountain with the Ten Commandments of God. By comparison on the day the Holy Spirit of God descended upon the disciples of God in the upper room on the day of Pentecost 3000 were saved.)
Paul is teaching us here religious practice according to the written instruction, even the Word of God, cannot save. Only a personal relationship with the Lord Jesus Christ can.
It was glorious for Moses to be in the presence of God, and it made his face radiant to such an extent his face was veiled from those who looked at him. But that glorious radiance faded away over time – and that is exactly how it is with religion. There is no abiding power to accompany the radiance and so it fades away.
But with faith in Christ comes the life of the Spirit of God within the heart, which makes us sufficient in every way the Word of God written on tablets of stone never could. Now the Word of God is engraved on the tablet of our heart, and it is ever-present, always available, and accompanied by the power of the Holy Spirit of God to do what the written word upon our heart commands us to do.
The written Word of God in religion is in and of itself glorious because it IS the Word of God. But all forms of religion, even those practiced according the Word of God are ultimately frustrating because the words tell you what to do without the power to do.
When you place your faith in Christ for salvation and are born again, the Holy Spirit of God is made alive in your heart, and He Himself becomes the Law for your life, according to the Word of God but also with the power of God to do what His Word says. This is the all-sufficient power Paul trusts to be at work in the lives of those in the church at Corinth, even though he cannot be there to instruct them face to face, and even if he could be.