Rabbi Adin Steinsaltz writes:
Hasidic teaching has a concept called d’veikut (“attachment”).
D’veikut is the process by which a person retraces the phases of his own creation until he reaches the point at which he ceases to be a separate entity.
This is the state that the Zohar refers to as “being drawn into the body of the King”, to be “sucked in” and nullified within the divine essence.
This is comparable, if such a thing would be possible, to a child retracing the phases of his conception and reverting to be once again a mere thought in the mind of his father.
We said that the Godly soul derives from the “thought and wisdom” of God.
The Alter Rebbe qualifies this by quoting the Zohar, which states that “He is wise, but not by any knowable wisdom”;.
Although we refer to God as “wise” and possessing wisdom, this is not a wisdom of the sort that we are capable of understanding or relating to in any way.
His is a wisdom of an entirely different sort, the most basic distinction being that “He and his wisdom are one.”
A human being’s wisdom–his knowledge and understanding–is something additional to his self.
He knows and understands things that are, for the most part, outside of himself.
Therefore, his wisdom is also something distinct from him.
He relates to it; he is deeply influenced and even transformed by it.
But he and it always remain two distinct entities: himself and the wisdom he possesses.
–Rabbi Adin Steinsaltz