Living Letters

It’s clear that you are Christ’s letter, written as a result of our ministry. You are a letter written not with ink but with the Spirit of the living God, a letter written not on tablets of stone but on tablets of human hearts.
Christ gives us confidence about you in God’s presence. He has also qualified us to be ministers of a new promise, a spiritual promise, not a written one. Clearly, what was written brings death [the Law], but the Spirit brings life. (2 Corinthians 3:3, 4, 6 GWT)

A true life testimony for God takes place when the Spirit of God transforms our stony, hard hearts. He softens them by His Spirit of grace.