“Beware of the yeast of the Pharisees, which is hypocrisy. For there is nothing covered that will not be revealed, or hidden that will not be known. Therefore what you have said in the darkness will be heard in the light. And what you have whispered in the ear in private rooms will be proclaimed on the housetops.
The worst sickness of Faith is hypocrisy. This is the reason why many Christians have a weak or ineffective faith. It is because of hypocrisy, lack of integrity, what you say does not match what you do.