1 John 3

The one who genuinely follows Jesus will be motivated by such great love to remain pure in their daily lives, knowing that one day Jesus will return and we will be completely like Him.  If we seek to remain in our fellowship with Him, we will keep our lives free from contaminants that cannot abide in His presence.  One's fruits (their deeds) show their roots (what is really at the center of their character).  This is why the world system is antagonistic to the things of Christ; at the center of the world's character is a hatred and disgust for the things of God.  However, at the center of God's character (and, by extension, His followers) is love for one another, a love that expresses itself in genuinely good deeds that please God and build others into what pleases God.