2 Corinthians 3:4

2You are our letter, written in our hearts, known and read by all men,

3being revealed that you are a letter of Christ, served by us, written not with ink, but with the Spirit of the living God; not in tablets of stone, but in tablets that are hearts of flesh.

4Such confidence we have through Christ toward God,

5not that we are sufficient of ourselves to account anything as from ourselves; but our sufficiency is from God,

6who also made us sufficient as servants of a new covenant, not of the letter but of the Spirit. For the letter kills, but the Spirit gives life.