When it comes to sin, one ploy that our non-glorified consciences use is to minimize it. Even if we are not Roman Catholic and standardize the practice by referring to venial and mortal sins in our theology, in our daily living we can have a practical theology that utilizes categories such as these. Certain acts we like to excuse by downplaying them.
Jerry Bridges addressed this tendency in his book _Respectable Sins, _where he shows how certain sins such as anger, worldliness, or lack of self-control are tolerated because, for one, they are not seen as that serious. They can be viewed as "little s" sins.
We do not downplay these sins when we see them in others. Oh, no. We are great splinter finders but horrible log identifiers. One has said that we look at others' sins through a telescope to magnify them, and look at our own sins through the telescope backwards to minimize them.
One means of engaging in wholehearted sanctification is to understand that so-called little sins can be the deadliest of all. A little lie, a little theft, a little glance - just a little selfishness can result in ruined lives. The Bible teaches us this in the grave simplicity (pun intended) of Adam's fall. One bite brought death's blight on us all.
If you need some real life examples of this truth, watch the following video called "From One Second to the Next" (HT: David Murray). These heart-wrenching stories about people who were texting while driving should not only cause us to give up even the thought of so doing. Seeing this pain should also sensitize us to how deadly any sin is, and remind us to daily seek the cleansing mercies of Christ to present every member of our body to Him for righteousness.