יַכְרֵ֣ת יְ֭הוָה כָּל־שִׂפְתֵ֣י חֲלָק֑וֹת לָ֝שׁ֗וֹן מְדַבֶּ֥רֶת גְּדֹלֽוֹת׃
여호와께서 모든 아첨하는 입술과 자랑하는 혀를 끊으시리니
Shemirat HaLashon
There is yet another general tikkun distinctive for the trait of lashon hara, and that is Torah study, as stated in Arachin 15b: "R. Chamma b. R. Chanina said: 'What is the amendment for the speakers of lashon hara? If he is a Torah scholar, let him occupy himself with Torah, as it is written (Proverbs 15:4): 'The healer of the tongue is the tree of life,' and the tree of life is none other than Torah, as it is written (Ibid. 3:18): 'It [Torah] is a tree of life to those who hold fast to it.'" As to its being called "a tree of life" — "Death and life are in the hand of the tongue" (Ibid. 18:21). If so, one who speaks lashon hara acquires for himself eternal death, wherefore Scripture counseled one who wished to heal his tongue to eat from the tree of life, which is Torah, "and he shall eat [thereof] and live forever."
Mivchar HaPeninim
38. The true believer only condescends to flatter when he pursues wisdom.
Sha'arei Teshuvah
The third section: The flatterer who praises the evildoer to his face, yet his wisdom restrains him - for he does not praise him in front of [other] people, lest he be a stumbling block for them. The sin of this flatterer is also great, as he blandished him in his eyes; such that he will not repent from his evil path and not worry about his iniquities - for he is righteous in his eyes. And when they praise anyone who is not from the congregation of the righteous - he will say in his heart, “Indeed, I knew that it was like this''; like the matter that is stated (Proverbs 11:9), “The flatterer destroys his neighbor through speech; but through knowledge, the righteous is rescued.” The explanation is that the flatterer destroys his neighbor with his mouth, because he will praise him and [the neighbor] will believe [his] words. So he will harden his spirit and he will see himself with honor, and not understand that his soul is murky. And with this stumbling block in his hand, he will fall into the trap of his pride. So behold, he surely destroyed him with his flattering lips. “But through knowledge, the righteous is rescued”: The righteous are saved from the damage of the flatterer through their knowledge. For if he flatters him, his heart will not be elevated as a result, like our Rabbis said (Niddah 30b), “Even [if] all of the world says about you, ‘You are righteous’ - be like an evildoer in your [own] eyes.” And they [also] said (Avot D’Rabbi Natan 29), “If you have companions, some of whom praise [you], and some of whom reprimand [you] - love the ones that reprimand you, and hate the ones that praise [you]. For these are bringing you to life eternal, and those, when they praise you, are gladdening you to your [own] detriment." And it is also possible to explain [it as]: “Through knowledge, the righteous rescue” their neighbors - as they will not flatter them; but will rather reprimand them and show them the path, when they err in the chaos that is not a path. And it is stated (Proverbs 26:28), “and a flattering mouth throws one down.” This compares a flattering mouth with a crooked path; and it says that just like a man falls and is thrown down by walking on a crooked path - like the matter that is stated (Psalms 35:5-6), “Let them be as chaff, etc., the Lord’s angel throwing them down. Let their path be dark and slippery” - so too does a man fall and get thrown down by a flattering mouth. And that is the mouth of the flatterer. And about the matter that we are discussing, King David, peace be upon him, said (Psalms 12:4), “May the Lord cut off all flattering lips, every tongue that speaks arrogance.” He cursed a flattering mouth, since he destroys his neighbor with it; and a harsh tongue - which is the opposite of the smooth [one], and that is evil speech. And among the flatterers, there are those that intend to flatter intimidating people, in order that they should honor them and promote them. And our Rabbis said (Avot D’Rabbi Natan 29), “Anyone that flatters his fellow for the sake of honor will in the end be removed from it in shame.”