Martyn Lloyd-Jones was not known as "The Doctor" merely because he had a medical degree. He was a master spiritual diagnostician, and skillfully applied treatment with God's Word to our condition. The following extract is a good example of this, dealing as it does with the nature of sin and its relationship to our prideful independence, which we today call "self-sufficiency."

"The fatal mistake is to think of sin always in terms of acts and of actions rather than in terms of nature, and of disposition. The mistake is to think of it in terms of particular things instead of thinking of it, as we should, in terms of our relationship to God. Do you want to know what sin is? I will tell you. Sin is the exact opposite of the attitude and the life which conform to, 'Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength.' If you are not doing that you are a sinner. It does not matter how respectable you are; if you are not living entirely to the glory of God, you are a sinner. And the more you imagine that you are perfect in and of yourself and apart from your relationship to God, the greater is your sin. That is why anyone who reads the New Testament objectively can see clearly that the Pharisees of our Lord's time were greater sinners (if you can use such terms) than were the publicans and open sinners. Why? Because they were self-satisfied, because they were self-sufficient. The height of sin is not to feel any need of the grace of God. There is no greater sin than that. Infinitely worse than committing some sin of the flesh is to feel that you are independent of God, or that Christ need never have died on the cross of Calvary. There is no greater sin than that. That final self-sufficiency, and self-satisfaction, and self-righteousness, is the sin of sins; it is sin at its height, because it is spiritual sin . . . ."

Lloyd-Jones, D. M. God's Way of Reconciliation - An Exposition of Ephesians 2. Grand Rapids: Baker Book House, 1972, p. 33.