Can a being know if It knows everything?

[freebs2]

I'm actually not a religious person but I attend a catholic university so I had to study for an obligatory theology exam.
For the exam I had to ream a book titled: "The Religious Sense" written by Luigi Giussani (a catholic priest).
I've found the book very interesting, it definetly hasn't converted me, but it changed a bit the vision I had about religions. In other words it helped me clear my mind on what being religious really means.
So I suggest everyone who wants to elaborate on this argument to read it.

http://books.google.it/books/about/The_Religious_Sense.html?id=WYF3Y_zT8zoC&redir_esc=y
Review: "Giussani challenges us to penetrate the deepest levels of experience to discover our essential selves, breaking through the layers of opinions and judgments that have obscured our true needs. Asserting that all the tools necessary for self-discovery are inherent within us, he focuses primarily on reason, not as narrowly defined by modern philosophers, but as an openness to existence, a capacity to comprehend and affirm reality in all of its dimensions. Part of the so-called new religious revival, The Religious Sense avoids any sentimental or irrational reduction of the religious experience. It is a forthright and refreshing call to reassess our lives."

In awser to the OP, it's very reductive to think the meaning of beliving in god is about believing in an omiscent being, the meaning of religion is more like believing there is an anwser that explains everything, that gives a meaning to all reality.
For christian, and for many other religions as well I guess, god is considered the creator so he knows everything about reality because he has created it. Also, according to christian religion, god knows everything about a person and his inner feelings and needs, still he gives any person the free will to decide whether to believe and follow him, or not.