In Hab 2:4, Rom 1:17, Gal 3:11, and Heb 10:38 the Bible tells us, "The just (righteous, pleasing/acceptable to God) shall live (eternal life) by faith (trusting/believing what God has said)." Such faith is rational. All other faiths are irrational.
You are driving on a residential side street, stopped at a busy thoroughfare to turn right. On your left you see an approaching cement mixer with its right turn signal on. If you believed the driver of that truck was indeed going to turn right onto your residential street, you would (by faith) proceed with your right turn before the truck turned right. But what if the truck does not turn right? Rationally, when should you make your right hand turn? Probably "by sight, rather than by faith", right?
Does every driver with a right turn signal blinking turn right? Do people say one thing but do another? Should we believe what people say or what they do? Do man-made things ever fail? Faith in people and their traditions/philosophies/religions is irrational.
Because He is God that cannot lie, Jesus Christ ALWAYS does what He says. The Word of God is truth that has never failed. Faith in Jesus Christ is rational.