The above verse is the first appearance in the Bible of the word 'writing.' Interesting, too, that it does not refer to the writing of man, but the writing of God.
This reference is to the Ten Commandments written on the stone tablets and given to Moses, and was "written with the finger of God," according to Exodus 31:18. And, in addition, God himself wrote the commandments a second time - on a second set of stone tablets, to replace the first tablets after they were shattered (Exodus 34:1).
This is incredible. I remember the first time that passage sunk into my mind. I must have read it many times before I spotted that. It is an amazing fact.
There is a third writing of God, this time in the New Testament, and it is even more exciting to the Christian. "Ye are manifestly declared to be the epistle [letter] of Christ ... written not with ink, but with the Spirit of the living God; not in tables of stone, but in fleshy tables of the heart" (2 Corinthians 3:3).
We Christians are letters! We are letters personally written by the Spirit of God! To what purpose? We are God's letters "known and read of all men" (2 Corinthians 3:2). We are God's letters to the world. Astounding.
What an awesome honor and responsibility we have.