From The Book of Zohar, "Introduction of The Book of Zohar," Essay, "Letters of Rav Hamnuna Saba," Item 37
The Letter Bet entered
And said to Him:
"Lord Almighty,
It is good for You to create the world with me,
Since through me You are blessed
From Above and below,
As Bet means blessing."
The Creator agreed
That its virtue was worthy
Of creating the world with it,
And He said:
"Certainly I will create the world with you,
Since the light of your blessing shines equally
Above and below,
And you will be the beginning
With which to Create the world."
Why is the letter Bet a good and sufficient beginning
To lead the world to ultimate wholeness?
Because it is the light of the blessing,
The Light of Mercy, which is the temple of the Light of Wisdom.
This Light never dims at all
As it passes and cascades through the degrees.
Just as it receives from Infinity at the highest degree,
It maintains its merit and its greatness in the world of Atzilut
And through the end of the world of Assiya.
It does not thicken or become blemished at all
As a result of all those screens through which it passes.