"It was said that whenever Rabbi Yonatan ben Uziel sat down to delve into the Torah, any bird straying over his head was burnt by his words." [Sukkah 28a]

"No fly passed over the table of the prophet Elisha." [Berachot 10b]

The Baal Shem Tov taught: Wherever a person's thoughts are, so is he surrounded by spiritual worlds that mirror his thoughts. If his thoughts are holy, so is he surrounded by holy worlds, but if his thoughts are impure, so is he surrounded by impure worlds.
Wherever a person's thoughts are, so is he surrounded by spiritual worlds that mirror his thoughts.
By the same token, wherever a person's thoughts are, and whichever worlds surround him, so is he surrounded in this earthly world, be it with kosher birds and animals, or non-kosher birds and animals.

[In the source text, (Ben Porath Yoseph 56d-57a) the Baal Shem Tov adds that whatever happens to a person is also a mirror of his inner world. Thus, G·d is constantly talking to each and everyone of us, trying to make us aware of what is going on inside us. And hence, when we see some human act "out there" that is "non-kosher," we should look inside ourselves for similar failings, rather than judge the other person.]

And there are three categories of worlds: the pure, the impure, and the in-between. Above these categories is the world of pure thought, which cannot be fathomed.

This, then, is why any bird straying above Rabbi Yonathan son of Uziel was burnt, and why no fly passed over Elisha's table, by way of which his host knew that he was a holy man, because his thoughts were holy.

["Straying birds" is an allusion to straying thoughts, which were "burnt" by Rabbi Yonathan's Torah study. Similarly, no fly, being a non-kosher creature, flew over Elisha's table, because his thoughts were always holy.]

Biographical note:
Yonatan ben Uziel lived 2000 years ago. He was the greatest of all the students of Rabbi Hillel. Known for his famous Targum [Translation and commentary] of the Prophets, it is said [Megillah 3a] that he also planned to author a translation-commentary on the "Writings" [Hagiographa] but was prevented by Heaven so that he would not reveal the secrets of the final redemption. For more about him and the frequent pilgrimages to his burial site near Tzefat, see Help for the Lovelorn.


Translation from Keter Shem Tov and commentary in brackets by Rabbi Yehoshua Starrett.
Reprinted with permission from //baalshemtov.com.