Hayom Yom: Menachem Av 20

Just as with the mitzva of tefillin for example, there is a designated place for them on the head and arm, and one feels the weight of the head-tefilla and the tightness of the hand-tefilla, so too with the mitzvot of ahava and yira, love and fear (awe) of G‑d. As Rambam writes, in Yesodei Hatorah 2:1: It is a commandment to love and fear the revered and awesome G‑d, as it is said, "Love Hashem your G‑d", and "You shall fear Hashem your G‑d."

Now the degree of fulfillment of these mitzvot is that there be a bodily sensation, that the very flesh of the heart actually feel (the love or the fear); just as, for example, when one meets a truly devoted friend. Not only does he feel good and forget all his troubles, he even enjoys a newly-awakened inner liveliness and optimism - all stemming from his cheerful mood.

So, too, with (the opposite emotion of) fear (of G‑d); he is seized by a great dread and fright, for at that moment he recalls whatever was undesirable in his thoughts, words and deeds. His heart feels a palpable pain from his dread of punishment, his fear of Heaven. At times he may experience yirat boshet, an overwhelming shame,1 or yirat harom'mut, awe of G‑d's transcendent majesty.2