Book of Formation - Sefer Yetzirah

Chapter VI

Mishnah 8, part 3

Mishnah * VI.8.3.  And He [G-d]  made a covenant with him [Abraham] between the ten fingers of his hands,

and [this covenant] is the holy language [Hebrew].

He [G-d] connected twenty-two letters to his [Abraham's] tongue,

and the Holy One, blessed be He, revealed their secret to [Abraham].

Companion

Mishnah VI.8.3.  [VI.4]  made a covenant - A second covenant, but only with Abraham.

between the ten fingers of his hands - There are nine gaps between ten fingers.

between the ten fingers of his hands - Only one gap is between the two hands.  Each hand represents the page of a book.  When the palms of the hands are held facing up, the spine of this "book" lies where the two pinky fingers are adjacent.

Also, the five fingers of each hand as held together hint at the Two Tablets of the Law that would be given to Moses close to 500 years later.

[this covenant] is the holy language - It seems to me that Abraham's secular language was the language of a the region called Aram.  Since this early time, the language has been called Aramaic.  Like all other languages, it is consensual.  The meaning of words change, people add new words and drop old words.

The Hebrew language, in contrast is the Divine language.  G-d alone has decided the meaning of its words.

* Definitions and Pronunciation