More evil is done to the cause of Christianity by its adherents than its opponents, for the world often contrasts a Christian's profession with his practice. They argue rightly that if Christianity is what we claim it is, it ought to make a difference in the life.

James Spink, cited in William MacDonald, The Forgotten Command: Be Holy
[1]
The inconsistencies of Christian people, who while professing to believe their Bibles were yet content to live just as they would if there were no such Book, had been one of the strongest arguments of my skeptical companions.

Hudson Taylor, cited in William MacDonald, The Forgotten Command: Be Holy [2]

If you have looked at your resolutions, endeavors, workings, duties, qualifications, etc., more than at the merits of Christ, it will cost you dearly....Christ alone can be the hope of glory (Colossians 1:27 [3]).

Thomas Wilcox, 1621-1687