See to it that no one fails to obtain the grace of God; that no root of bitterness springs up and causes trouble, and by it many become defiled.
Nosh: Unresolved bitterness is like a cancer. The longer one has it the more it spreads and makes the embittered person sick. It is also a contagion, i.e. it infects and defiles everyone around them with a bitter and negative spirit.