The Mishnah in Avos (3:11) states that someone who unmasks the face of the Torah contrary to the law (המגלה פנים בתורה שלא כהלכה) has no share in the world to come. The phrase “unmasking the face of Torah” is vague and requires explanation. The phrase “contrary to the law” is missing in many manuscripts.
I. Rejecting Some of the Torah
Rashi (ad loc.) says that it means someone who denigrates the Torah by stating that certain verses are superfluous. This is based on the Gemara (Sanhedrin 99b) which equates someone who unmasks the face of the Torah with Menasheh, the wicked king of Israel. Previously on the same page, the Gemara describes Menasheh’s questioning the necessity of various verses. Evidently, Rashi connects the two passages. Commenting on the latter passage on the page, Rashi writes that someone who unmasks the face of the Torah is not only questioning its necessity but also rejecting it. In other words, the denigration and questioning of various verses is a way of denying the correctness and divine origin of those verses. This denial of the divine origin of even a few verses is unacceptable, as the Gemara makes clear on the prior page (99a): “Even if one accepts that the whole Torah is from Heaven except for one verse, which was not said by God but by Moshe on his own, he is included in ‘Because he has despised the word of the Lord’ (Num 15:31).” This is also the way Rabbenu Yonah explains it in his Sha’arei Teshuvah (3:144).
In a contemporary application, Gordon Tucker, the editor and translator of Prof. Abraham Joshua Heschel’s Heavenly Torah as Refracted Through the Generations, writes in a footnote (p. 376 n. 20: “Heschel here presents the view attributed to Manaseh as if it were an anticipation of the modern Documentary Hypothesis, which ‘reveals the face’ of the different literary strands that were interwoven by a redactor to produce the current book.”
II. Reinterpreting the Commandments
The Rashbatz (Magen Avos 3:15) takes this in a slightly different way. He includes people who accept the written Torah as completely binding but then derive from it laws that contradict the oral Torah. For example, the Mishnah in Megillah (25a) states that someone who translates Lev. 18:21 as “You shall not impregnate a Non-Jewish woman” (rather than “You shall not let any of your descendants pass through the fire to Molech”) is to be silenced. This is a case of unmasking the face of the Torah in a manner contrary to the law. This is also the approach of the Tiferes Yisrael (ad loc., no. 74). Prior to the Rashbatz, the Meiri had already taken this further, in response to what was a growing problem in his time. He applies this label to anyone who allegorizes verses in the Torah, but not any verse — specifically commandments. Anyone who allegorizes a commandment to the point of saying that it is not obligatory (i.e. he permits eating pig) is considered someone who unmasks the face of the Torah contrary to the law.
III. Publicly Disobeying the Torah
The Rambam (commentary to Avos, ad loc.) explains it to mean someone who publicly violates Torah laws, the unmasking of the face referring to a certain audacity that is required. Rabbenu Yonah, in his commentary to Avos, agrees with the Rambam’s interpretation. This is based on the Talmud Yerushalmi in Pe’ah (1:1). It specifically explains that “someone who unmasks the face of the Torah” refers to a person who publicly violates the laws of the Torah, like King Yehoyakim. A casual reader of the Bible might be surprised by that. Granted, the Bible says that Yehoyakim was wicked, but where does it describe him violating Torah laws in public? I don’t see it in 2 Kings 23 or 2 Chronicles 36. However, 2 Chronicles 36:8 does refer to “the abominations which he did” but no detail is given. There are some bad stories about him in Sanhedrin 103a-b but I don’t see anything about public transgressions. Evidently, according to the Yerushalmi, they were bad.