It seems to me that people are capable of having faith in virtually anything. Since people can have faith in things that are clearly false, how can anyone claim that faith is required in order to comprehend truth?
In the case of God and His Religions we have three criteria to accept it as a source of Truth.
They all offer their Person, their Life and then Word they give from God as proof. This in turn inspires many people to build the Faith in them, which in turn helps the progress of Humanity in the age the Message is given.
This is a quote from Baha'u'llah;
"...Say: The first and foremost testimony establishing His truth is His own Self. Next to this testimony is His Revelation. For whoso faileth to recognize either the one or the other He hath established the words He hath revealed as proof of His reality and truth. This is, verily, an evidence of His tender mercy unto men. He hath endowed every soul with the capacity to recognize the signs of God. How could He, otherwise, have fulfilled His testimony unto men, if ye be of them that ponder His Cause in their hearts. He will never deal unjustly with anyone, neither will He task a soul beyond its power. He, verily, is the Compassionate, the All-Merciful....."
Regards Tony