Let’s assume that this church billboard is real. This church may espouse something like this
1) All x (whatever x is) are enemies of faith
2) Reason is an occurrence of x
3) Therefore, Reason is an enemy of faith
I assume that, because of this belief, they think Christians shouldn’t use reason. So their reasoning goes like this
4) We should not use anything that is the enemy of faith.
5) Reason is the enemy of faith.
6) Therefore, we should not use reason.
Surely they used reasoning to come to the conclusion that reason is the enemy of faith and that we should not use it. I guess they don’t have much faith then, since they are obviously using reason all the time. Oops!