Thief

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-Bahá, Bahá’í World Faith, p. 412-413