Hasidic idea of being attached or cleaving to God.
Reprinted from The Jewish Religion: A Companion, published by Oxford University Press.
Devekut is an attachment to God, having God always in the mind, an ideal especially advocated in Hasidism but found, too, in earlier Jewish writings. The term devekut, from the root davak, to cleave, denotes chiefly this constant being with God but sometimes also denotes the ecstatic state produced by such communion. The relevant verse is found in the book of Deuteronomy, a book replete with the summons to love God, in the verse: "To love the Lord thy God, to walk in all His ways and to cleave unto Him" (Deuteronomy II: 22).
The Talmudic rabbis understand the cleaving to God mentioned in the verse as referring to the Torah and its students. Being attached to the Torah and its study constitutes the only possible cleaving to God at all applicable to finite human beings who can never actually 'cleave' to God Himself. But in a notable passage, Maimonides (Guide of the Perplexed, 3. 51) develops the idea that it is possible for the greatest saints to have God always in the mind. Such saints, says Maimonides, are immune from the common mishaps of human life. As their minds are on the highest, nothing on earth can affect them; they can even walk through fire and water without suffering an harm.
Hasidism relies on this passage but, following a comment by Nahmanides to the verse, extends the ideal as attainable by lesser mortals, although, in its fullest sense, it can only be attained by the Hasidic master, the Zaddik. Nahmanides writes in his commentary:
"The verse warns man not to worship God and a being beside Him; he is to worship God alone in his heart and in his actions. And it is plausible that the meaning of "cleaving" is to remember God and His love constantly, not to divert your thought from Him in all your earthly doings. Such a man may be talking to other people, but his heart is not with them since he is in the presence of God. And it is further plausible that those who have attained this rank, do, even in their earthly life, partake of the eternal life, because they have made themselves a dwelling place of the shekhinah."
The Hasidic ideal of "serving God in corporeality," that is, serving God by having the mind on Him even when engaging in business or other worldly pursuits, is based on Nahmanides' understanding of the ideal of devekut. It was also in obedience to this ideal that Hasidism understood the rabbinic doctrine of "Torah for its own sake" to mean that when studying the Torah the mind should be on God. This attempt to convert the study of the Torah from an intellectual into a devotional exercise angered the mitnagdim, the opponents of Hasidism, because, for them, to study with anything in mind other than the subject studies, is not to study at all.