John 8:32:

And ye shall know the truth, and the truth shall make you free.

Notes on John 8:32:

The truth only makes you free when you know it.  It was already true that Jesus hung on a cross and paid the full punishment for your sins before you were born again.  However, you were not free until you KNEW that truth.  It is the same with healing or anything else.

Some preachers love to use this as a pay-attention trick: “The truth shall make you free, Amen!  No, wrong, ha-ha, gotcha!  You have to know the truth before it makes you free.”  While this is so, it is very annoying when preachers do this, especially because “The truth shall make you free” is correct in this verse, even though its context is that you have to know it.  Actually, it is rather irritating when a preacher deliberately misquotes scripture to see if he can catch people who are not really paying attention.  I don’t see Jesus doing that, so I never do it.

See also:

How to Deal with the Devil