The whole Bible tells us, from beginning to end, that salvation is not by the works of the law, but by the deeds of grace. Martin Luther declared that he constantly preached justification by faith alone, “because,” said he, “the people would forget it; so that I was obliged almost to knock my Bible against their heads, to send it into their hearts.” So it is true, we constantly forget that salvation is by grace alone. We always want to be putting in some little scrap of our own virtue; we want to be doing something. I remember a saying of old Matthew Wilkes: “Saved by your works! you might as well try to go to America in a paper boat!” Saved by your works! It is impossible! Oh no; the poor legalist is like a blind horse going round and round the mill; or like the prisoner going up the treadmill, and finding himself no higher after all he has done; he has no solid confidence, no firm ground to rest upon. He has not done enough—“never enough.” Conscience always says, “this is not perfection; it ought to have been better.” Salvation for enemies must be by an ambassador—by an atonement—yea, by Christ.
~Charles Spurgeon~
The New Park Street Pulpit Sermons, Vol. I (London: Passmore & Alabaster, 1855), 155. Vol. 1, Sermon No. 20; Titled: The Carnal Mind Enmity Against God; Delivered on Sabbath Morning, April 22nd, 1855.