The Torah in Parashat Re’eh (Debarim 13:9) issues a series of five commands relevant to a situation of a “Mesit” – somebody who tries to lure others to engage in the worship of foreign deities. If a person is found to be involved in such efforts, the Torah demands that he be treated very harshly, and it issues five distinct prohibitions that apply in such a case.
The first is “Lo Tobeh Lo,” which is understood to mean that we must not show the “Mesit” any sort of fondness or affection; he must be looked upon with sheer contempt, and not be made to feel good about himself.
Secondly, the Torah commands, “Ve’lo Tishma Elav” (“Do not listen to him”), which means that we must not try to remove from our hearts our feelings of contempt for this individual. Elsewhere (Shemot 23:5), the Torah commands that if somebody whom we have legitimate reasons to dislike requires our assistance, “Azob Ta’azob Imo” – we must help the individual despite our negative feelings toward him. Targum Onkelos translates this phrase to mean that we must abandon our feelings of hostility toward that person and extend to him the help he needs. In the case of a “Mesit,” however, the Torah specifically commands us to retain our hostile feelings toward this person, and forbids us from trying to change our outlook and overcome our contempt for him.
Thirdly, the Torah commands in this verse, “Ve’lo Tahos Alav” (“Do not show him pity”), which means that we must not rescue the “Mesit” from situations of danger. Normally, of course, we are forbidden to remain idle when a fellow Jew faces danger, and we must do what we can to save him (“Lo Ta’amod Al Dam Re’echa” – Vayikra 19:16). The exception to this rule is the “Mesit,” whom the Torah forbids us from rescuing, due to the unique severity of his actions, seeking to lure other Jews to worship idols.
The next command in this verse, “Ve’lo Tahmol” (“Have no compassion”), applies in the courtroom setting, forbidding bringing arguments in favor of the “Mesit.” In all other situations of a defendant who stands trial, every effort must be made to argue in his favor, to find reasons for an acquittal. In the case of a “Mesit,” however, the Torah commands that to the contrary, no argument may be brought on behalf of the “Mesit” for the purpose of avoiding a conviction.
Finally, the Torah in this verse commands, “Ve’lo Techaseh Alav” (literally, “Do not cover for him”), which forbids withholding information or arguments which could lead to the conviction of an accused “Mesit.” One who has an argument for convicting the defendant must speak up, and may not remain silent.
The Sefer Ha’hinich explains that the Torah’s exceptionally harsh treatment of the “Mesit” is due to the exceptionally egregious nature of his sin. As he actively works to lead Jews away from the belief in, and worship of, the true G-d, and toward the worship of idols, he is not entitled to mercy or compassion. The Sefer Ha’hinuch adds that this applies also to other exceptionally wicked individuals – people “who have no hope,” meaning, they’ve deteriorated to a level of evil from which they cannot be realistically expected to recover. Specifically, the Sefer Ha’hinuch explains, he refers to those who ridicule the Hachamim and seek to harm them. Such people must be treated harshly, like a “Mesit.”
The Midrash famously cites the teaching of Rabbi Yehoshua Ben Levi, “Whoever is compassionate to the cruel person, becomes cruel toward the compassionate one.” If we “mix the wires” in one direction, showing love and compassion to a truly evil person who is undeserving of love and compassion, then we are likely to then “mix the wires” in the opposite direction, as well, and show cruelty to those who deserve compassion. Thus, while normally, of course, the Torah demands that we treat people lovingly, kindly, sensitively and mercifully, there are exceptional circumstances of especially wicked people who must be treated harshly, such as the “Mesit,” missionaries who make a concentrated effort to lure Jews away from their faith.