“Loving sin is worse than committing it.” – Thomas Watson, The Doctrine of Repentance (1668)
“It is the case of most sinners to think themselves freest from those sins to which they are most enslaved.” – Richard Baxter, The Causes and Danger of Slighting Christ and His Gospel (17th Century)
“All sin must be wept over; here, in godly sorrow, or, hereafter, in eternal misery.” – Matthew Henry, Commentary on the Whole Bible (1706)
For more quotes like these gems check out The Complete Guide to Christian Quotations.