Musar do Wyjścia 32:31

And secondly, for this [too] is one who speaks evil speech considered as if he denied a fundamental principle: For he says in his heart that his lips are in his [own] control; and because they do not do an action and he is in charge of his tongue, he determined in his heart that he should not restrain the spirit of his lips from saying that which comes to his spirit; and that only all the other limbs are not in his control to sin with them - like the matter that is stated (Psalms 12:5), “They say, “with lips such as ours, who can be our master?” And they do not say, “Where is the God that made me, to whom all the movements of His creations are given - not one is lacking. They are all subjected to doing His will. Rather, it is no matter - the petitions about the lips are in our control.” The evildoers that sin with other sins are not like this. For they know that their leaving God is bad and bitter, however they were pulled after their desire and their overpowering [evil] impulse; yet they are pained by this. And our Rabbis said (Arakhin 15b), “Evil speech [...] corresponds to three transgressions [and these are them]: Idol worship, forbidden sexual relations and bloodshed. [...] With regard to idol worship, it is stated (Exodus 32:31), ‘Oh, this people have sinned a great sin.’ With regard to forbidden sexual relations, it is stated (Genesis 39:9), ‘How can I do this great wickedness.’ With regard to bloodshed it is stated (Genesis 4:13), ‘My punishment is greater than I can bear.’ [And with regard to evil speech,] it is stated (Psalms 12:4), “May the Lord cut off all flattering lips, the tongue that speaks great things.”

How great is the power of lashon hara, which is over and against three grave transgressions, as stated in Arachin 15b. And in Midrash Shocher Tov: "The school of R. Yishmael taught: 'All who speak lashon hara mount iniquity over and against three transgressions: idolatry, illicit relations, and the spilling of blood, it being written here (Psalms 12:4): 'the tongue that speaks "great" [i.e., slanderous] things'; but, in respect to idolatry (Shemoth 32:31): 'I pray you — this people has sinned a great sin'; in respect to illicit relations (Bereshith 39:9): 'And how shall I do this great evil?'; in respect to the spilling of blood (Ibid. 4:13): 'My sin is too great to bear'" — whence [("things" - plural)] it is derived that lashon hara is severer than these three sins." Another explanation: One who kills a man kills only one soul; but one who speaks lashon hara kills three: the speaker, the accepter, and the one spoken about. Whence do you derive this? From Doeg, who spoke lashon hara about Achimelech before Saul, and the three of them were killed: Saul, who accepted it; Achimelech, who was spoken about; and Doeg, who spoke it. Saul, who accepted it, viz. (I Samuel 31:6): "And Saul died, etc."; Achimelech, who was spoken about, viz. (Ibid. 22:16): "Die, shall you die, Achimelech"; and Doeg, who spoke it, who was driven out of the world [to come], viz. (Psalms 52:7): "G-d also will destroy you forever" from life in the world [to come]. And what caused this? Lashon hara.

Abraham bound his son, and the Holy One, Blessed is He, swore to remember this merit to the credit of his children for generations and generations. When Israel sinned with the golden calf, Moses, upon him is peace, stood in prayer and said: "Remember the deeds of Abraham, Isaac and Israel thy servants" (Exod. 32:31), and so Solomon prayed : "Remember the good deeds of David Thy Servant" (II Chron. 6:42), and their prayers were answered. And thus we mention every day the merits of the fathers (in our daily prayers).