I’m going to start a new category: Graffiti. This categtory will offer some great quotes.
I don’t know many that would top the following from Luther:
“If you are a preacher of grace, then preach a true and not a fictitious grace; if grace is true, you must bear a true and not a fictitious sin. God does not save people who are only fictitious sinners. Be a sinner and sin boldly, but believe and rejoice in Christ even more boldly, for he is victorious over sin, death, and the world.
As long as we are here [in this world] we have to sin. This life is not the dwelling place of righteousness, but, as Peter says, we look for new heavens and a new earth in which righteousness dwells. It is enough that by the riches of God’s glory we have come to know the Lamb that takes away the sin of the world. No sin will separate us from the Lamb, even though we commit fornication and murder a thousand times a day. Do you think that the purchase price that was paid for the redemption of our sins by so great a Lamb is too small? Pray boldly—you too are a mighty sinner.”
-Martin Luther, in a letter to Phillip Melancthon
GRACE & PEACE 
Similarly:
In every incident of the Mystic Way the great cross-bearer of the Universe cries in our ears, “Accept, accept! Live boldly, dangerously, and completely without fastidiousness. Accept the mud and slime, the heat and misery, the odious disabilities of the flesh. Accept the rabble, the ignominious struggles, and the falls. Wisdom’s path is no swept and shaded avenue, but the hard and beaten highways of the World. This is the straight way to God. Accept.
John Cordelier, The Path of Eternal Wisdom
And Teresa of Avila
“He gilds my faults.’