After much time spent on Google, I have managed to locate an article that quotes the aforementioned letter from R’ Dessler on Emunas Chachamim:
Rabbi Dessler’s letter concerning faith in the sages (emunat chakhamim) opens with criticism of the questioner:
This introduction gives us a fairly clear idea of the question that had been posed to Rabbi Dessler. Since the letter is dated 1944, the issue was a burning, fraught one: at this very time the annihilation of Jews was proceeding at full speed. News of what was going on in Europe was circulating, but precise information had still not made its way to many places. Thus, for example, further on in the same letter Rabbi Dessler speaks of Rabbi Elchanan Wasserman in the present tense, while in fact he had been murdered three years previously. Rabbi Dessler sets forth his reply as follows:
“First of all I want to tell you that I had the merit to know several of these great ones personally, and I have observed them at meetings on matters concerning Klal Yisrael; such as the Chafetz Chaim of sainted memory, Rabbi Chaim Brisker of sainted memory and Rabbi Chaim Ozer of sainted memory; and I can tell you with all sincerity that the amazing agility of their minds could be perceived even by puny intellects such as ours; the depth of their wisdom penetrated down into he very abyss; there was not the slightest chance that anyone like you or me could follow completely the crystal-like clarity of their understanding. And more: whoever was present at their meetings could see with his own eyes the extent and depth of the sense of responsibility with which they approached these matters; it could be seen on their faces, when they deliberated for the sake of Heaven and devoted their minds to considering the problems of Klal Yisrael. Anyone who did not see this has never seen feelings of responsibility in his life. Whoever had the merit to stand before them on such an occasion could have no doubt that he could see the Shekhina resting on the work of their hands and that the Holy spirit was present in their assembly. One could certainly make the blessing “He Who separates between holy and profane” on the difference between their meetings and the kind of meetings we are used to nowadays.
I expect you are aware of what Rabbi Elchanan Wasserman (may he live a long life) relates concerning the spiritual power of his teacher, the Chafetz Chaim of sainted memory. You must know, my revered friend, that Rabbi Elchanan is certainly very great, and it would be wrong to set aside his words, much less to reject them, because of what we puny people think that we see with our own eyes. Our Rabbis have told us to listen to the words of the Sages “even if they tell us that right is left,” and not to say, God forbid, that they must be wrong because little I “can see their mistake with my own eyes.” My seeing is null and void and utterly valueless compared with the clarity of their intellect and the divine aid they receive. No Beth Din can revoke the decrees of another Beth Din unless it is greater in number and in wisdom; failing this it is very likely that what they think they “can see with their own eyes” is merely imagination and illusion. This is the Torah view concerning faith in the Sages.”
Rabbi Dessler’s response adopts a virulent tone quite uncharacteristic of his writings in general. He devotes his main efforts to describing the greatness and righteousness of such leaders as the Chafetz Chaim, Rabbi Chaim Ozer Grodzinsky, and Rabbi Elchanan Wasserman, who negated Zionism and discouraged aliya. By virtue of their greatness, he argues, their guidance as leaders should not be viewed as the advice of mortal leaders; rather “the Holy Spirit is present in their assembly.” In other words, when such great and righteous Jewish sages gather together, it is impossible for their conclusions to be mistaken.