Rabbi Schachter: No. The pasuk in Navi (Malachi 2:7), as expounded by the gemara (Moed Katan 17a), says that a Torah teacher must be sinless and righteous like a malach (angel). According to the Torah, we only follow a rabbi’s ruling if he properly models Torah behavior. If he is a ba’al aveirah, if he knowingly violates Biblical or rabbinic laws, he is not qualified to teach and render halachic rulings. When members of the public become aware of his improper behavior, they may no longer rely on his judgment for any rulings, unless it can be verified that such rulings were rendered before the rabbi’s sinful conduct began. Since it is often not possible to ascertain when these rulings were rendered, one should ask another rabbi for a new pesak.
Although people use [Marcus] Jastrow’s [Aramaic] dictionary [for Talmudic and Midrashic terminology], and I was told that Jastrow was not Orthodox, that is different because that is an issue of translation, not pesak (halachic adjudication). For a pesak, a rabbi needs to consider all issues before him, and weigh and evaluate them. It is very different than mere translation. To issue halachic rulings, one must be part of the chachmei haMesorah (Torah scholars who follow the Torah’s traditions). A rabbi who sins, especially if he commits a crime, is certainly not in this category.
שְׁלֹשָׁה חֲכָמִים הֵם: הָרוֹאֶה רַבִּי בַּחֲלוֹם — יְצַפֶּה לְחׇכְמָה. רַבִּי אֶלְעָזָר בֶּן עֲזַרְיָה — יְצַפֶּה לַעֲשִׁירוּת. רַבִּי יִשְׁמָעֵאל בֶּן אֱלִישָׁע — יִדְאַג מִן הַפּוּרְעָנוּת.
There are three Sages whose appearance in a dream is significant: One who sees Rabbi Yehuda HaNasi in a dream should anticipate wisdom; one who sees Rabbi Elazar ben Azarya should anticipate wealth, as he was particularly wealthy; and one who sees Rabbi Yishmael ben Elisha should be concerned about calamity.


ת"ר ארבעה נכנסו בפרדס ואלו הן בן עזאי ובן זומא אחר ורבי עקיבא
§ The Sages taught: Four entered the orchard [pardes], i.e., dealt with the loftiest secrets of Torah, and they are as follows: Ben Azzai; and ben Zoma; Aḥer, the other, a name for Elisha ben Avuya; and Rabbi Akiva.
בן עזאי הציץ ומת ... בן זומא הציץ ונפגע ועליו הכתוב אומר (משלי כה, טז) דבש מצאת אכול דייך פן תשבענו והקאתו אחר קיצץ בנטיעות רבי עקיבא יצא בשלום
The Gemara proceeds to relate what happened to each of them: Ben Azzai glimpsed at the Divine Presence and died. And with regard to him the verse states: Ben Zoma glimpsed at the Divine Presence and was harmed, i.e., he lost his mind. And with regard to him the verse states: “Have you found honey? Eat as much as is sufficient for you, lest you become full from it and vomit it” (Proverbs 25:16). Aḥer chopped down the shoots of saplings. In other words, he became a heretic. Rabbi Akiva came out safely.


בכיבוד אב ואם כתיב (דברים ה, טו) למען יאריכון ימיך ולמען ייטב לך בשילוח הקן כתיב (דברים כב, ז) למען ייטב לך והארכת ימים
With regard to honoring one’s father and mother it is written: “That your days may be long, and that it may go well with you” (Deuteronomy 5:16). With regard to the dispatch of the mother bird from the nest it is written: “That it may be well with you, and that you may prolong your days” (Deuteronomy 22:7).
ואחר מאי הוא איכא דאמרי כי האי גוונא חזא
The Gemara asks: And what caused Aḥer to sin? There are those who say he saw a case like this, where a son went up to the roof on his father’s command, dispatched the mother bird, and then died. It was witnessing this episode that led Elisha ben Avuya astray.
אשכחיה רבה בר שילא לאליהו א"ל מאי קא עביד הקב"ה א"ל קאמר שמעתא מפומייהו דכולהו רבנן ומפומיה דר"מ לא קאמר א"ל אמאי משום דקא גמר שמעתא מפומיה
The Gemara relates: Rabba bar Sheila found Elijah the prophet, who had appeared to him. He said to Elijah: What is the Holy One, Blessed be He, doing? Elijah said to him: He is stating halakhot transmitted by all of the Sages, but in the name of Rabbi Meir He will not speak. He said to him: Why? He replied: Because he learned halakhot from the mouth of Aḥer. He said to him: Why should he be judged unfavorably for that? Rabbi Meir found a pomegranate and ate its contents while throwing away its peel.


