No matter how much we may study, it is not possible to come to know God unless we live according to His commandments, for God is not known by science, but by the Holy Spirit. Many philosophers and learned men came to the belief that God exists, but they did not know God. It is one thing to believe that God exists and another to know Him. If someone has come to know God by the Holy Spirit, his soul will burn with love for God day and night, and his soul cannot be bound to any earthly thing.
-St. Silouan the Athonite