My doctor recently removed a suspicious mole from my neck. Thankfully, it was benign. But suppose it had been malignant. And suppose further that I hadn't mentioned it to her because, for whatever reason, I thought it was "no big deal?" Clearly, ignoring such a mole would have given cancer free reign to my body, and eventually I would have died a very nasty death.
Suppose my seemingly insignificant mole represents sin; an obvious analogy, perhaps, but one we really should revisit. Sin usually seems as if it's "no big deal," but Scripture says it always grows like a cancer until it causes the death of separation from God. So be obedient to rid yourself of any sin the moment you see it.