Holiness is not something we are called upon to do in order that we may become something. It is something we are to do because of what we already are. There is a great deal of teaching on this subject that really amounts to this: we are to be holy and live the holy life in order that we may become truly Christians. Every phase or aspect of the doctrine of justification by works really teaches that. But any suggestion we may have in ourselves that we are to deny ourselves certain things, that we are not to do certain things, and that we are to discipline ourselves in order that we may become Christian is a denial of the doctrine of justification by faith. I am not to live a good and holy life in order that I may become a Christian. I am to live the holy life because I am a Christian. I am not to live this holy life in order that I may enter heaven. It is because I know I am going to enter heaven that I must live this holy life.
That is the emphasis here: “Every man that hath this hope in him purifieth himself, even as He is pure” (1 John 3.3). I am not to strive and sweat and pray in order that, at the end, I may enter into heaven. No, I start, rather, from the standpoint that I have been made a child of God by the grace of God in the Lord Jesus Christ. I am destined for heaven. I have an assurance that I have been called to go there and that God is going to take me there, and it is because I know this that I am preparing, now. – D. Martyn Lloyd-Jones (1899-1981)