Rashi comments (Devorim 1:13):
And understanding: -- who understand one thing from another. This is what Arius asked of Rabbi Yose: What is the difference between wise men and understanding men? A wise man resembles a wealthy money-changer: When people bring him "dinars" to examine [and exchange] he examines them, but when they do not bring them to him he (merely) sits and does nothing. An understanding man resembles a merchant money-changer, when people bring him money to examine, he examines them and when they do not bring it to him, he seeks about and brings money of his own.
The Lubavitcher Rebbe suggests that what is going on under the surface is a discussion of... Trinity:
"Arius was an early christian bishop who established a new denomination in christianity which emphasized unity in G-d, as opposed to the standard christian belief in the trinity. As a result of his "heresy," he was denounced, disrobed and exiled, but was later reappointed to his station.
The difference between unity and trinity in Arius's philosophy may be analogous to the difference between secular wisdom and understanding. Unity symbolizes the unitary spark of wisdom, while trinity alludes to the three stages of understanding. Therefore, Arius who represented unity (wisdom) questioned and challenged the "understanding" of trinity. "
Sichos In English
Volume 32
Shabbos Parshas Devorim
4th Day Of Menachem Av, 5746
The explanation is daring and striking. The curious application of Chabad categories of thought to christian sectarianism shows the incredible breadth of knowledge and universal scope of the Rebbe's concerns.
St. Nicholas beating up Arius (actually he looks like he is pulling his ear...):
Arianism was one of several heresies the fight against which submerged the Roman Empire in blood and undoubtedly hastened its demise. More, here.
This knowledge is of potential halachic significance in establishing various denomination as idolatrous, or not. Unitarians (or Oneness Pentecostalists) might not be halachically ovdei avodah zara (even according to those who would consider Christianity (shituf) avodah Zara) and it may be persmissible to enter their churches for a purpose.

This is not an accurate description of Arianism. Classic Christianity teaches that the Trinity - three co-equal "persons" co-substantial, all eternal,in one godhead. Arianism taught that only the Father was eternal; and the second person - the Son - was not eternal nor of equal divinity - rather he was created. According to this definition, Arianism may actually be a more classical case of "shituf" - worshiping a Divine person together with a "less" divine person. You seem to - in error - equate Unitarians and Oneness Pentecostals. Unitarians generally do not acknowledge the divinity of JC - where as oneness pentecostals acknowledge his divinity - but teach a doctrine that the trinity is not persons - but "modes" or "expressions" - very similar to the Hindu idea of one Gd with Brahma being the "creator"; Vishnu the "preserver" and "Shiva" destroyer (although this is, as well, only one view ). Pardon me for getting into a lengthy discussion of this topic - but I have a "thing" for accuracy. BTW - it doesn't surprise me that the late Lubavitch rebbe had a Yedia in these subjects.
Posted by: Simcha | August 04, 2008 at 11:02 PM
Thank you for the explanation. I included some links but did not want to get into the involved discussion since that was not the point of the post. I am not sure, however, that arianism is shituf because it may be understood as J. being a demigod, neither fully god nor man, and this is how Arius' detractors tried to protray what he taught. His own writings did not in majority survive and what he himself believed is not exactly known.Some of what I read contended that Unitariansim is close to Arianism and draws inspiration from it.In any case, I probably already know more about this than I should.
Pico Della Mirandolla and other Christian Kabbalists wrote a lot about Trinity as modes of expression but my understanding is that the Church officially denounced Pico's formulation of Trinity as Chochma, Bina, Daat to be heretical.
The Lubavitcher Rebbe had an amazing grasp of many areas of knowledge.The chiddush here is that he allowed himself to gain knowledge in this area.
Posted by: avakesh | August 05, 2008 at 01:24 PM
can somone post the text of the rashi?
Posted by: yu | August 12, 2008 at 10:38 PM