Hasidic thought draws heavily on Lurianic Kabbalah, and, to an extent, is a popularization of it. Teachings emphasize God's immanence in the universe, the need to cleave and be one with him at all times, the devotional aspect of religious practice, and the spiritual dimension of corporeality and mundane acts. "Hasidim", the adherents of Hasidism, are organized in independent sects known as "courts" or dynasties, each headed by its own hereditary leader, a "Rebbe". Reverence and submission to the "Rebbe" are key tenets, as he is considered a spiritual authority with whom the follower must bond to gain closeness to God. The various "courts" share basic convictions, but operate apart and possess unique traits and customs. Affiliation is often retained in families for generations, and being Hasidic is as much a sociological factor – entailing, as it does, birth into a specific community and allegiance to a dynasty of "Rebbe"s – as it is a purely religious one. There are several "courts" with many thousands of member households each, and hundreds of smaller ones. , there were over 130,000 Hasidic households worldwide, about 5% of the global Jewish population.