Purity.

1 Thessalonians 4v7-8
For God has not called us for impurity, but in holiness. Therefore whoever disregards this, disregards not man but God, who gives his Holy Spirit to you.

Our purity is extremely important to God. We see it all through out scripture. Not only does purity prove Gods power in us on the outside (to those around us) but more importantly on the inside. Our body is a temple and not our own we must treat it like so, sacrificing desires of flesh and denying what the devil wants so badly: our soul, our inner thoughts, our Spirit.

1 Corinthians 6v19
Or do you not know that your body is a temple of the Holy Spirit within you, whom you have from God? You are not your own.