Hebrews 12:14-15
Make every effort to live in peace with all men and to be holy; without holiness no one will see the Lord. See to it that no one misses the grace of God and that no bitter root grows up to cause trouble and defile many.
It is these troublemakers who defile many. These troublemakers have "missed the grace of God". What is the grace of God? The grace of God is full Christformation in you. Once you miss that, the sinful nature of the Devil matures within you. The "bitter root that grows" within you will mature you to become troublemakers, hence defiling many more around you so that, like you they too will keep obeying the sinful nature of the Devil in them. Such troublemakers seek to increase men and women who are stubborn and rebellious towards the LORD on this Earth, wherever they go or through whatever they seek to do with their lives. The idea is to defile as many as they can through their lives. They are truly "bitter and defiled", therefore like them they want others to be defiled too. Take heed that you can only be defiled by the sinful nature of the Devil in you. Don't let that "bitter root" called the sinful nature of the Devil in you to mature you into a troublemaker for everyone around you. Put it to death instead, before it causes more trouble for everyone and defile many. Sit and down and think and turn from your evil ways, you deliberate troublemakers before it's too late! Give serious thought to your ways now!
Psalms 140:9-10
Let the heads of those who surround me be covered with the trouble their lips have caused. Let burning coals fall upon them; may they be thrown into the fire, into miry pits, never to rise.