1 John 3:3 And every man that hath this hope in him purifieth himself, even as he is pure.
4 Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law.
These verses show us the hope we have if we keep ourselves pure. Verse 4 reminds us that even though we are under grace the law is still the standard by which we judged. When we sin today it is because we have transgressed against the law. But again if we will strive each day to keep our life in line with the will of God we know the hope that we hold dear of being in Heaven with Him will be a reality one day. This verse also lets us know that each and every one of us is responsible for own salvation.