Faith is necessarily the opposite of reason. It's an equivocation fallacy. And a common one many theists make which is easily dismissed.
"Faith, as the Bible describes it, is not a matter of empirical observation, even though some like to present it as if it were. In fact, the Bible praises a man’s faith
to whatever extent he ignores the empirical data. The more contrary to the observable facts a man’s belief is, the greater faith he is said to have. It praised Noah for building a boat before there was even any rain. It praised Abraham for expecting children even though he was (as the story goes) over 100 years old and was apparently infertile. It praised Gideon for expecting a military victory despite what appeared to be the worst tactical plan in history. On and on it goes, celebrating those whose beliefs flew directly in the face of their observable circumstances. This is not a mode of perception or decision-making which follows empirical data. It is not a matter of forming hypotheses based on what you see and experience. In fact,
it is explicitly and expressly the opposite idea. To have faith, in the biblical sense, is hold onto a belief which is unsupported by what you see or experience. The more at odds the former is with the latter, the greater
faith you have."
http://www.patheos.com/blogs/godlessindixie/2014/12/01/do-atheists-have-faith-2/