I've been reading a book called Of the Mortification of Sin in Believers by the puritan writer, John Owen. And I must say, although he wrote this book a few centuries ago, it captures insights on sin to the extent that i've yet to see in any modern writer. Here's one section that really spoke to me as I was reading this morning:
"Rise mightily against the first actings of your distemper [or temptation]; suffer it not to get the least ground. Do not say, 'Thus far it shall go, and no farther.' If it have allowance for one step, it will take another. It is impossible to fix bounds to sin. It is like water in a channel; if it once break out, it will have its course. Its not acting is easier to be compassed than its bounding. Therefore does James give that gradation and process of lust (1:14-15), that we may stop at the entrance. Do you find your corruption to begin to entangle your thoughts? Rise up with all your strength against it, with no less indignation than if it had fully accomplished what it aims at. Consider what an unclean thought would have; it would have you roll yourself in folly and filth. Ask envy what it would have; murder and destruction is at the end of it. Set yourself against it with no less vigor than if it had utterly debased you to wickedness. Without this course you will not prevail. As sin gets ground in the affections to delight in, it gets also upon the understanding to slight it."
I pray that this will speak to you as it has spoken to me, that we fight sin with everything we have (with the help of the Holy Spirit) to the day we die.