In verse 3, Paul uses this metaphor of a letter of commendation to lead into a discussion comparing the Old and New Covenants. "You are manifestly an epistle of Christ, ministered by us, written not with ink but by the Spirit of the living God, not on tablets of stone but on tablets of flesh, that is, of the heart." When God made the Old Covenant with ancient Israel, Moses wrote the commandments, statutes and judgments that God had given to him in a book with "ink" (
Exodus 24:4). God wrote the Ten Commandments with His own finger on two tablets of stone (
Exodus 31:18;
32:15-16). However, Paul points out, under the New Covenant, God has given us His Spirit, enabling us to keep His laws in their spiritual intent. He is now writing His Ten Commandments on our hearts (
Hebrews 8:10)!