Musar do Diwrej ha-jamim II 36:26

But the one who does not get aroused by the voice of his rebukers will double his iniquities. For they reprimanded him and he hardened his heart - as it is stated (Proverbs 17:10-11), "A rebuke works on an intelligent man, more than one hundred blows on a fool. An evil man seeks only to rebel; a cruel messenger will be sent against him." The explanation is that the evil man will not submit to the voice of the rebukers. Rather he will seek to rebel. And since he did not stop from the words of the reprimanding angel, a cruel angel will be sent against him - measure for measure. For rebukers are called angels (malakhim, which literally means messengers), as it is stated (II Chronicles 36:16), "But they mocked the messengers of God and disdained His words and taunted His prophets." And King Solomon, peace be upon him, also said (Proverbs 15:10), "Discipline seems bad to him who forsakes the way; he who spurns rebuke will die." Its explanation is [that] it is true that harsh rebuke is appropriate for one who has forsaken the way and transgresses the words of the Torah. However there is hope that he will take the rebuke and repent from his evil way. But worse than him is one who hates rebuke. For he has no hope and rectification from harsh rebuke. Rather his one verdict is to die. For one who does a transgression - his desire overpowered him and the impulse pushed him. But it is likely that his soul is bitter about that which he was [not stronger] in the face of his impulse. And maybe he longs for reprimand and hopes for reproof. But one who hates reprimand has already abandoned his soul; and his hatred for reprimand will be a proof that he hates the words of God, may He be blessed.

Keeping this in mind, we can understand the statements of Rabbi Shmuel bar Nachmeini in Chulin 91a who says that Samael appeared to Jacob as a pagan, whereas Rav Shmuel bar Acha thought that Samael appeared to Jacob in the guise of a Torah scholar. These two views need not conflict with one another, Considering the impurity that radiates from Esau, Samael appeared like a pagan; considering the holiness that radiates from the angelic aspect of Samael, he appeared like a Torah scholar. Just as the features of Jacob are engraved on the throne of G–d, so the features of Esau must be perceived as engraved on Samael. More than once in Scripture are Torah scholars equated with angels, to quote only וישלח מלאך ויוציאנו, "G–d sent an angel and he took us out” (Numbers 20,16, the angel being Moses). Rashi, commenting on that verse, also quotes Chronicles 11, 36, 16: ויהיו מלעיבים במלאכי האלהים, "They insulted the "angels" of G–d," as referring to the prophets. At that particular time, Samael decided to don human garments in order to wrestle with Jacob physically. After Jacob had bested him, Samael concealed the evil part of himself and became a "good" angel. In that latter capacity he confirmed that Jacob had deserved Isaac's blessing and then himself blessed him. As soon as that happened, peace between Jacob and Esau was restored in our world.

The sin of machloketh obtains even if one argues with another who is equal to him in status. How much more so, G-d forbid, if he argues with a Torah scholar, even if he is not his Rabbi. How much more so if he is his Rabbi, is his sin great and his wickedness redoubled. For it is well known that the way of men of machloketh is to shame by words those who oppose them. And the greatness of the punishment of one who shames a Torah scholar is well known from what is stated in Sanhedrin, Chapter Chelek, and is ruled in Yoreh Deah 234:6, that one who shames a Torah scholar is in the category of (Numbers 15:31): "For the word of the L-rd he has despised. That soul shall be utterly cut off; its sin is in it." And even in our day, if he be but fit to rule [on halachah] and toils in Torah, he is called a Torah scholar. And if one shames him, even in general matters, and even not in his presence, it is a grave sin and he is liable to nidui [excommunication] because of this (as we find in Yoreh Deah 246:7 and in the Shach section 68.) And there is also no cure for his illness, as we find in Shabbath 119b: "R. Yehudah said in the name of Rav: 'If one shames a Torah scholar, there is no cure for his illness.'" And the destruction of Jerusalem also is attributed to this sin, as we find there: "Jerusalem was destroyed only because Torah scholars were shamed there, as it is written (II Chronicles 26:16): 'And they shamed the angels of G-d [i.e., the Torah scholars], and scorned His words and mocked His prophets until the wrath of the L-rd rose against His people, without cure.'" They have also said (Berachoth 19a): "R. Yehudah b. Levi said: 'All who slander a Torah scholar after his death descend to Gehinnom.'"

The exertion is that which a man completely detaches and removes himself from the physical, and clings always, at all periods and times to his G-d. In this manner, the prophets were called "angels", as said of Aharon: "For a priest's lips shall guard knowledge, and Torah shall be sought from his mouth; for he is an angel of the L-rd of Hosts" (Malachi 2:7), and it is said: "but they mocked the angels (prophets) of G-d" (Divrei Hayamim II 36:16). Even when he is engaged in physical actions required for his bodily side, his soul will not budge from its clinging on high. This is as written: "my soul clings after You; Your right hand supports me"(Tehilim 63:9).