This phrase is internally false; it is nothing more than a distortion and reversal of the intent of the verse in Habakkuk (2:4): “But the righteous person shall live by his faith.” As explained in the Gemara (Makkot 24a), Habakkuk came and based the 613 mitzvot given to us upon one principle. That is, the entire Torah is built upon faith in the righteousness of the path—but faith that stems from righteousness, meaning from the desire to do what is right, by seeking and pursuing the truth. When one recognizes that there is a Creator of the world and delves deeply into this knowledge and all its implications, he can arrive, through this understanding, at knowledge and fulfillment of all the mitzvot. This is not so regarding one who does whatever he feels like doing, because of his desires, bad habits, or distorted views that have entered his mind and dulled it. Certainly, it was not said of such a person that he shall live by his belief.
We can now understand that one who says, “A man shall live by his faith,” is declaring that there is no absolute truth—that, Heaven forbid, there is no Creator of the world who determined what must be done, but rather that each person should follow the desires of his heart and the feelings of his stomach.
It may be added that it seems that these heretics did not choose the word “man” without reason, since it alludes to the verse (Deuteronomy 12:8), “Every man [does] whatever is right in his own eyes,” concerning which the Torah warns us: “You shall not do so!”
Accordingly, if “the righteous person shall live by his faith” is the great foundation upon which the entire Torah stands, its opposite is the uprooting of the entire Torah. Therefore, one must eradicate and uproot this outlook, hold fast to righteousness, and establish our faith upon it—not through knowledge alone, but by living accordingly and living it at every moment and in every situation, as it is written (Deuteronomy 4:39): “Know today and take it to your heart that Hashem is God in the heavens above and upon the earth below; there is none other.”
All this does not contradict the fact that Judaism contains a variety of approaches and styles, both those arising from differing views and perspectives, and those arising from differences of personality and suitability. Our Sages already said (Ta’anit 31a): “In the future, the Holy One, blessed be He, will make a circle dance for the righteous, and He will sit among them in Gan Eden, and each one will point with his finger and say: ‘This is Hashem for whom we hoped.’” The commentators explain that the circle dance is a circle, in which every point is equally distant from the center, alluding to the fact that there are indeed many paths in the service of Hashem, and all are directed toward the center, which is the Holy One, blessed be He. The statement of Chazal is also well known (Bamidbar Rabbah, parashah 13, section 15) that there are seventy facets to the Torah, as is the concept found in the Gemara (Eruvin 13b): “These and these are the words of the living God.”
However, there are, of course, the Thirteen Principles of Faith, which every person is obligated to believe. Likewise, a person must observe all 613 mitzvot of the Torah, as Moshe received them at Sinai, as our Sages explained them throughout the generations, and as they are ruled in the Shulchan Aruch. Regarding this, a person cannot say that he lives by his own faith and does not accept the fundamentals of Judaism, or that he does not feel like observing the laws of the Shulchan Aruch. For the truth of Judaism does not depend on personal preference or majority opinion; rather, it is absolute and binding truth. All other religions are merely a pathetic imitation of Judaism, and atheism is nothing but casting off the yoke under the guise of ideology and philosophy.
May it be Hashem’s will that you merit to clarify and know the truth, instill it in your heart, and walk in it all the days of your life.
With blessings,
Rabbi Eliyahu Beracha