Keter Torah MiSinai

ומנלן דהתורה נקראת ברכה
Sefer HaBahir, verse 3 excerpt

Traditional interpretation: "How do we know that Torah is called a blessing?"

תטהרו

דהתורה has a gematria of 620, the same gematria as the word keter (the level of Torah revealed at Sinai), the number of letters in the Torah text of the ten commandments, the full number of the mitzvot, the number of pillars of light which "connect the ceiling of keter to the floor of malchut" [1], and the gematria of the word "titharu" which alludes to the revelation of keter in imma ila'ah.

טהרות

It's all here, in the word דהתורה.

Footnote:

[1] R' Yitzchak Ginsburgh, The Inner Dimension