Christians are not sinners but saints. In this he takes seriously that the believer is a new creation. This is no innovative teaching. Puritan Richard Sibbes wrote in his sermon Josiah's Reformation: The Tender Heart
“It is a supernatural disposition of a true child of God to have a tender, soft, and a melting heart.”Whereas he argues that naturally the heart is
“a stony heart… say what you will to a hard heart, it will never yield. A hammer will do no good to a stone. It may break it in pieces, but not draw it to any form. So to a stony heart, all the threatenings in the world will do no good. You may break it in pieces, but never work upon it. It must be the almighty power of God. There is nothing in the world as hard as the heart of man..... “How then do you get a new heart?
“...Tenderness of heart is wrought by an apprehension of tenderness and love in Christ. A soft heart is made soft by the blood of Christ… I am sure nothing will melt the hard heart of man but the blood of Christ, the passion of our blessed Saviour… When a man considers of the love that God has showed him in sending of his Son, and doing such great things as he has done, in giving of Christ to satisfy his justice, in setting us free from hell, Satan and death: the consideration of this, with the persuasion that we have interest in the same, melts the heart, and makes it become tender… because with the preaching of the gospel to broken-hearted sinners cast down, there always goes the Spirit of God, who works an application of the gospel.”What should we do with a tender heart to keep it soft? Should we treat it with law and tell it how to behave? No, Sibbes goes on to argue that we should:
“be always under the sunshine of the gospel.”We treat a renewed heart with the gospel of the Lord Jesus. It is the grace of God that teaches us. Those who are converted by the gospel, stay with the gospel. Those who begin with the Spirit, continue with the Spirit. Indeed the only way to live the Christian life, with a new heart, will be to be filled again and again with the Holy Spirit, who alone will produce change. To treat my own sin with law and rules is to fail to take sin seriously, it's to say I can fix myself. The only option for the true child of God is to be changed by the Triune God - to pursue the work of the Holy Spirit whom the Father, who sent his son into the world, has sent into our hearts (Galatians 4:4-6).