From the Rebbe’s explanations:
– HaShem created the world with two sides: “This one opposite the other”, that is the side of holiness and its opposing forces; the good inclination on the right side and the evil inclination on the left side. Since “The Torah which Moshe commanded us is the inheritance of the congregation of Yaakov,” it can be understood that a Jew’s side is the side of Torah and mitzvos and he has no relation to the other side at all.
Nevertheless, since a Jew still has freedom of choice, the Torah and its mitzvos are called “my side” and not “my existence”. The material nature of the world conceals G‑dliness and thus the possibility exists that a Jew – at first – will not appreciate the need to listen to the Torah’s directives.
What is the intent behind the creation of such circumstances? So that the Jew will transform the world (even those aspects that on the surface oppose the Torah and its mitzvos), and have the Torah internalized within it.
The question then may arise: How is it possible for a Jew to cause the Torah to be internalized within the world? Up to the point of “drawing all the peoples of the world to follow the seven laws which are obligatory for all the descendants of Noah” (according to the Rambam in “Hilhot Mlahim” this is one of the tasks entrusted to Mashiach). After all, won’t he become a part of the world and start behaving accordingly?
This question is also answered by the word tzadi, “my side”.
As a Jew exists within this material world, he seems to retain the view of an outside observer. His connection to the Torah and its mitzvos does not compel him to conduct himself in a certain manner. On the contrary, as mentioned above, he has free choice. Therefore, the Torah specifically instructs him:
And choose life [that is, the side of the Torah] (Nitzavim, 30:19).
Ultimately, however, he will choose Torah and mitzvos, making them “my side”. As soon as he makes such a decision, the Creator Himself (which is hinted at by the letter “yod” in the word “tsadi”) will immediately come to his side – as written in the book of Tehillim (109:31):
“For He will stand to the right of the needy to save [him] from those who judge his soul”.
From the Rebbe’s talk on Shabbat Parshat Tzav, 8th Day of Nissan, 5751 (1991).