"The Kabbalah was never a conspicuous part of the daily life of the Jewish people.
To be more precise, we would say that the Kabbalah as a conscious study was restricted to a small elite.
This was usually a closed circle of people who could devote themselves to it—not only because of the intellectual complexities of the Kabbalah, but because, more than in any other field of Jewish tradition, a very great moral purity was required of the student.
Such a high level of moral and spiritual experience could scarcely be expected of an ordinary person.
In any case, by its very nature, the pursuit of esoteric wisdom is limited to a chosen few.
Nevertheless, the Kabbalah has had such a profound influence on the tradition that one may even see it as the theology of Judaism.
This is especially true of the last five hundred years or so—in spite of the fact that in our own time the Kabbalah is just beginning to emerge from the obscurity into which it was thrust by enlightened rationalism.
What is apparent, however, is the influence of the Kabbalah on almost all the features of daily life, from ancient times to the present.
True, not everyone is aware of it, but almost every Jewish custom is likely to have some kabbalistic significance or at least to have been fashioned by some such influence.
This means that the practical Kabbalah—not in its crude magic and miracle-making folk expressions, but in its deep penetration into the action, rituals and prayers, laws, language, and customs of the people—is still existent.
There is a core of those few who have made the Kabbalah a source of inner transformation and esoteric knowledge.
But there are widening circles whose authority was never significant but whose influence manages to be felt somehow.
To be sure, only the inner circle is likely to know the meaning of many of the old expressions and actions.
In the further circles, people simply know that this is the way things are done; certain words are said, ritual actions are performed without comprehending why or how they came into being.
From this point of view, the Kabbalah is still very much present—even if unknown to the majority of the people.
Most Jews would probably angrily reject the notion that many of their traditional modes of expression are 'kabbalistic.' "
--Rabbi Adin Steinsaltz
From On Being Free by Rabbi Adin Steinsaltz