As with any debate one must begin with a definition of the terms used. "Kabbalah" is a word meaning "receiving" or "that which has been received". If this debate were to ask "Did Abraham study the ten seferot and Ezekiel's Chariot, the answer would most probably been "NO". If it were to ask "Did Abraham drink Kabbalah water and e-mail Madonna, the answer would be a definite "NO". But the very foundations of the discipline we now call Kabbalah began at creation. At creation HaShem created Adam, the Adam Kadmon, the blueprint for all of creation. This Adam Kadmon was in the image of G-d, meaning, He was granted all the attributes of the ten seferot that reflected his creator. In this instance it would be safe to say that even Adam and Eve has some spark of the energy of Kabbalah that defined their existence.
Abraham was raised by a Pagan priest. According to Talmud his father was not only a priest but created idols of wood and clay to sell to the local pagan worshipers. As Abraham was working in his father's shop his "revelations" began growing, his understanding took hold and he "received" the concept that there is no gods that man can create who are truly gods. He could see that all of the world had a spirituality and an order. From this logic he deduced that there is ONE G-D, undefinable and uncontrollable, who created everything. This is Kabbalah. It is that spark of divine revelation that sets one apart from the ordinary and the common and helps us to receive the spiritual truths that create our world. As the story goes, Abraham broke all the statues except one. When his father came back he was appalled.
"Why have you destroyed all my income!" he screamed.
"oh father, it was not me. See this one large idol left, it destroyed all the others"
"You are lying. This idol is made of wood and stone. It can not move. It cannot destroy. It can do nothing". his father retorted.
"yes, father....and this is who you worship?"
We even have a parshat dedicated to Jethro. The only Torah portion named after a gentile. Because at this point Jethro, even, understood. He received the Truth that the G-d of creation is not made of stone or wood.
For hundreds of years the Kabbalah was only an oral tradition transmitted from one rabbi or torah scholar to another. One was not allowed to learn it by oneself. It was necessary to be at least 40 years old and have years in dedication to learning Torah before venturing into the study of the mystical aspects of Judaism. So what we see here is that Torah learning is the foundation of Kabbalah. That is precisely why Rav. Berg, and "Madonna Kabbalah" can never grasp the total truths of this mystical religion. I am not in opposition to the study of Kabbalah by those who are not torah observant, I am only opposed to their representing such a great pathway in such a trite way. And that is why I would like to include Abraham as a student in Kabbalah, He "received" the very foundations of Judaism and is an excellent representative of the paths of truth available to those who will "receive".