"What we have to grasp, then, is that the bad conscience of the natural man is not at all the same thing as conviction of sin. It does not, therefore, follow that a man is convicted of sin when he is distressed about his weaknesses and the wrong things he has done.
"It is not conviction of sin just to feel miserable about yourself and your failures and your inadequacy to meet life's demands. Nor would it be saving faith if a man in that condition called on the Lord Jesus Christ just to soothe him, and cheer him up, and make him feel confident again.
"Nor should we be preaching the gospel (though we might imagine we were) if all that we did was to present Christ in terms of a man's felt wants ('Are you happy? Are you satisfied? Do you feel that you have failed? Are you fed up with yourself? Do you want a friend? Then come to Christ; He will meet your every need...' -- as if the Lord Jesus Christ were to be thought of as a fairy godmother, or a super-psychiatrist.
"No, we have to go much deeper than this. To preach sin means, not to make capital out of people's felt frailties (the brainwasher's trick), but to measure their lives by the holy law of God.
"To be convicted of sin means, not just to feel that one is an all-round flop, but to realize that one has offended God, and flouted his authority, and defied Him, and gone against Him, and put oneself in the wrong with Him.
"To preach Christ means to set Him forth as the One who through His cross sets men right with God again. To put faith in Christ means relying on Him, and Him alone, to restore us to God's fellowship and favor."
-- J.I. Packer "Evangelism and the Sovereignty of God" pp. 60-61 (IVP)