When God made man in his own image, the moral law was written in his heart, by the finger of God, without outward means. But since the covenant then made with man was broken, the Lord has used the ministry of men, both in writing the law in the Scriptures, and in writing it in the heart.
When God was reconciled to the Israelites, he ordered the tables to be renewed, and wrote his law in them. Even under the gospel of peace by Christ, the moral law continues to bind believers. Though Christ has redeemed us from the curse of the law, yet not from the commands of it.
The first and the best evidence of the pardon of sin, and peace with God, is the writing the law in the heart.