The foundation of the Kingdom of God is laid upon justice, fairness, mercy, sympathy and kindness to every soul. Then strive ye with heart and soul to practice love and kindness to the world of humanity at large, except to those souls who are selfish and insincere. It is not advisable to show kindness to a person who is a tyrant, a traitor or a thief because kindness encourages him to become worse and does not awaken him. The more kindness you show to a liar the more he is apt to lie, for he thinks that you know not, while you do know, but extreme kindness keeps you from revealing your knowledge.
- ‘Abdu'l-Baha (‘Baha'i World Faith’)