We think of the concrete and the material as though it were something absolute, because our grasp of being and non-being is that it is identical with reality and the absence of reality.
Whereas, being is actually that which has independence, whose existence does not depend on something else.
And nonbeing, or nothing, is that which is the very opposite.
The fact that one sees matter as the primary aspect of the real makes for a world that is actually at a distance from reality and that is inappropriately called Being.
when we speak of the nullification of Being, it does not mean taking that which is and smashing it.
It signifies rather that the less the I assumes priority in the conscious mind, the more there is a nullification of Being.
In response to a question concerning the idea of "Unio Mystica"—the total obliteration of oneself —it may be said that it is not given to us to accomplish it in this world.
And in Judaism, whatever can be known of such "Union" exists only in one condition—within the mitzvah.
True, there are those who think that only a person who reaches a degree of unio mystica can truly fulfill the mitzvot.
The explanation is that the mitzvah is itself Divine unity.
And the illustration is given of someone who is clasped by the king, held in his embrace for a moment —in which case it doesn't matter what clothes He is wearing; it is the arm of the king that counts.
Just as, when I busy myself with Torah, it doesn't matter what the physical trappings of the book are.
The essential thing is the word of God that comes through.
And as soon as Torah enters my mind, I become united with it.
–Rabbi Adin Steinsaltz
From The Sustaining Utterance by Rabbi Adin Steinsaltz