Whatever weakens your reason, impairs the tenderness of your conscience, obscures your sense of God, or takes off the delight for spiritual things, whatever increases the authority of your body over your mind, that thing is sin. — Susanna Wesley, letter to her son John Wesley

The exercise of the mouth cannot change the heart. Your sin is like a prostitute. You are speaking against your lover in public but embracing her in the bedroom. She is not particular about being run down in public if she can have your full attention in private. — Jim Elliff

No man knows how bad he is till he has tried very hard to be good.  — C.S. Lewis

Sin is what you do when you are not satisfied in God.  — John Piper

Sin is believing the lie that you are self-created, self-dependent and self-sustained. — Augustine

What is sin? Sin is a species of rebellion against God. It is self-pleasing: it is the utter ignoring of God’s claims: being completely indifferent whether my conduct pleases or displeases Him.  — A.W. Pink

Sin is not merely wrong acts and thoughts, but sinfulness as well, an inherent inner disposition inclining us to wrong acts and thoughts. We are not simply sinners because we sin; we sin because we are sinners.  — Millard Erickson

We need to call sin what the Bible calls it and not soften it with modern expressions borrowed from our culture.  — Jerry Bridges

Sin is essentially a departure from God.  — Martin Luther

Sin is a deliberate treason against the majesty of God, an assault upon His crown, an insult offered to His throne.   — C.H. Spurgeon

Sin to a believer is horrible, because it crucified the Saviour; he sees in every iniquity the nails and spear. — Charles Spurgeon

Sin is not an unfortunate slip or a regrettable act; it is a posture of defiance against a holy God. — Max Lucado

Sinners, like those that are mad, destroy themselves with foolish lusts, and yet at the same time deceive themselves with foolish hopes; and they are, of all diseased persons, most enemies to their own cure. — Matthew Henry

The true Christian’s nostril is to be continually attentive to the inner cesspool. — C.S. Lewis

Either sin is with you, lying on your shoulders, or it is lying on Christ, the Lamb of God. Now if it is lying on your back, you are lost; but if it is resting on Christ, you are free, and you will be saved. — Martin Luther

Anybody who has once been horrified by the dreadfulness of his own sin that nailed Jesus to the Cross will no longer be horrified by even the rankest sins of a brother. Looking at the Cross of Jesus, he knows the human heart. He knows how utterly lost it is in sin and weakness, how it goes astray in the ways of sin, and he also knows that it is accepted in grace and mercy. Only the brother under the Cross can hear a confession. — Dietrich Bonhoeffer

The joy of the Lord will arm us against the assaults of our spiritual enemies and put our mouths out of taste for those pleasures with which the tempter baits his hooks.  — Matthew Henry

God’s wounds cure, sin’s kisses kill. — William Gurnall

God is not against us because of our sin. He is with us against our sin. — Anon.

One leak will sink a ship; and one sin will destroy a sinner.  — John Bunyan

Sin wouldn’t be so attractive if the wages were paid immediately. — Anon.

We have a strange illusion that mere time cancels sin.  — C.S. Lewis

We are wearied with our sins, and have no satisfaction in them; we go to bed tonight weary of our sinful labors, and we will rise freshly tomorrow to the same sinful labors again. — John Donne

Fallen man is not simply an imperfect creature who needs improvement: he is a rebel who must lay down his arms. — C.S. Lewis

When sin is your burden, Christ will be your delight.  — Thomas Watson