Walk in Christ's light daily through fidelity to personal and liturgical prayer, nourished by meditation on the inspired word of God.. Make the daily… - Benedict XVI

...when today as believers in our age we hear it said, a little enviously perhaps, that in the Middle Ages everyone without exception in our lands was a believer, it is a good thing to cast a glance behind the scenes, as we can today, thanks to historical research. This will tell us that even in those days there was the great mass of nominal believers and a relatively small number of people who had really entered into the inner movement of belief. It will show us that for many belief was only a ready-made mode of life, by which for them the exciting adventure really signified by the word credo was at least as much concealed as disclosed. This is simply because there is an infinite gulf between God and man; because man is fashioned in such a way that his eyes are only capable of seeing what is not God, and thus for man God is and always will be the essentially invisible, something lying outside his field of vision. ...

The glory of God is the living man, but the life of man is the vision of God', says St. Irenaeus, getting to the heart of what happens when man meets God on the mountain in the wilderness. Ultimately, it is the very life of man, man himself as living righteously, that is the true worship of God, but life only becomes real life when it receives its form from looking toward God.

I think the essential point is a weakness of faith.