2 Corinthians 4:7
But we have this treasure in earthen vessels, that the excellency of the power may be of God, and not of us.
Note 1 at 2Co 4:7: The treasure that Paul was speaking of is the light of God, shining in our hearts through Jesus Christ, as he spoke of in 2Co 4:6. Another way of defining this treasure is "Christ in you, the hope of glory" (Col 1:27). Paul was speaking of our present union with Christ and all the benefits that affords. This truly is a treasure, far beyond the price of money. It was purchased with the precious blood of Christ (1Pe 1:18-19).
Note 2 at 2Co 4:7: The earthen vessels that Paul was speaking of is our physical bodies. This is a metaphor to compare the relative worthlessness of our bodies to the matchless value of Christ in us. Our bodies are like clay pots that contain the precious treasure of Christ.
Note 3 at 2Co 4:7: Why didn't the Lord change our vile bodies (Php 3:21) at salvation to mirror the wonderful transformation that took place in our hearts? This verse gives the answer. He didn't want anyone mistaking the power that flows through us as being our own. He wanted full credit for this new life.
If you took your automobile to a mechanic who had all the latest computer equipment and robotics, you might leave there thinking about how fantastic that equipment was. However, if you took your car to a mechanic who only used the most basic tools and he fixed the problem, you would leave there impressed with the mechanic, not his tools. Likewise, it glorifies the Lord even more when His power is expressed through ordinary people. Those who notice have to say it's God and not the person doing the works (see note 11 at 1Co 1:27).