Devekut, from a Hebrew root meaning to cling or to adhere, names the ideal of sustained, intimate attachment to God that runs through medieval Jewish philosophy, Kabbalah and, in its most developed and popularized form, Hasidism. The term appears already in the Hebrew Bible, in the command to cling to the Lord your God, and medieval Jewish philosophers including Maimonides gave it an intellectualist reading, devekut as the mind's sustained contemplation of God reached through philosophical understanding. Kabbalistic writers gave the term a more experiential and theurgic sense, describing devekut as a state achieved through contemplative prayer and the performance of the commandments with focused inner intention, kavanah, in which the individual soul draws close to, without dissolving into, the divine emanations described in Kabbalistic cosmology.
The concept sits at the center of a long running internal Jewish conversation about how far human closeness to God can go while still preserving the fundamental distinction, insisted on across nearly all strands of Jewish theology, between the Creator and the created soul. Later Kabbalistic writers, including those associated with the school of Isaac Luria, folded devekut into a wider cosmological framework in which human contemplative attachment to God was understood to have effects on the upper worlds themselves.