Thou settest thyself with all diligence and earnestness to mortify such a lust or sin; what is the reason of it? It disquiets thee, it hath taken away thy peace, it fills thy heart with sorrow, and trouble, and fear; thou hast no rest because of it. Yea; but, friend, thou hast neglected prayer or reading; thou hast been vain and loose in thy conversation in other things, that have not been of the same nature with that lust wherewith thou art perplexed. These are no less sins and evils than those under which thou groanest, Jesus Christ bled for them also. Why dost thou not set thyself against them also? If thou hatest sin as sin, every evil way, thou wouldst be no less watchful against everything that grieves and disquiets the Spirit of God, than against that which grieves and disquiets thine own soul.
– John Owen –
from The Mortification of Sin in Believers, volume 6 of Works, page 41