A person who is constantly steeped in the world of Torah and piety is liable to lose the power of rejuvenation, not because he does not understand, but precisely because he understands.
After all, he has already heard everything; and if, by chance, he has never heard a particular idea, he has certainly heard something like it.
And even if the idea itself is totally novel, he is still uninterested, as he is already familiar with the subject.
It can happen that someone, during Shaharit, is struck by the sudden epiphany that he loves God.
This is a rare thing, which happens perhaps once a year.
Will he then jump onto the table and shout, “I love God!”?
Generally not.
But why not?
The answer is that there is a certain element of stam that dictates that – even when a point of inspiration comes to him – it would not be proper: One must follow the practice of the land of the Philistines.
In Jerusalem’s German Colony, there is a law that prohibits building above three stories.
Similarly, there are people who have an inner law to that effect, not to build above three stories, and not to delve beyond a certain depth:
It is against municipal regulations.
This is the custom of the land of the Philistines.
–Rabbi Adin Steinsaltz