2 Corinthians 3:4 Meaning

2Ye are our epistle written in our hearts, known and read of all men:

3Forasmuch as ye are manifestly declared to be the epistle of Christ ministered by us, written not with ink, but with the Spirit of the living God; not in tables of stone, but in fleshy tables of the heart.

4And such trust have we through Christ to God-ward:

5Not that we are sufficient of ourselves to think any thing as of ourselves; but our sufficiency is of God;

6Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.