Here are some great quotes addressing the issue of sin:

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

Sin doesn’t strike all at once. It kills slowly and persistently.
– Stephen Altrogge

What fools are they who, for a drop of pleasure, drink a sea of wrath.
– Thomas Watson

I have never heard of a sin being committed without knowing full well
that I had the seed of it within myself.
– Johann Wolfgang von Goethe

Beware of no man more than of yourself;
we carry our worst enemies within us.
– C.H. Spurgeon