Shemirat HaLashon שמירת הלשון

It is written in the Torah (Shemoth 2:14): "And Moses was afraid, and he said: 'In truth, the thing has become known,'" concerning which Rashi says that Moses wondered why Israel was smitten more than all the other peoples, and now he saw why they deserved this [i.e., because there was lashon hara among them.] Now is it not written in Ezekiel 20 that they were guilty of great sins, [among them] idolatry, an extremely grave sin, in spite of which he wondered at [the severity of] their afflictions! How is it, then, that because the sin of lashon hara was added to this that his wonder was allayed?

[This is resolved, however,] through the holy Zohar, viz.: When one speaks lashon hara he arouses the Great Adversary against Israel, which brings death, sword, and slaughter to the world. This is the language of the holy Zohar in Parshath Pekudei: "There is a certain spirit that stands over all those who speak lashon hara, and when men, or one man, stir up lashon hara, then there is stirred up that unclean spirit above called Sachsucha ('contention'), and it comes to repose upon that awakening of lashon hara initiated by men, and it ascends on high, and the stirring up of lashon hara causes death, sword, and slaughter in the land. Woe to those who stir up this evil agent and do not guard their mouths and their tongues and are not concerned about this, and do not realize that on the lower arousal is dependent the higher arousal, both for good or for evil, etc. And all conspire to awaken that Great Serpent to condemn the world. And all because of that awakening of lashon hara which is initiated below."

We have explained elsewhere that without the sin of the tongue, it would not be granted the power to make known on high the abominations of men and to demand din for them. [And now] all is clear. For Moses our teacher, too, may peace be upon him, knew that in Egypt there were many great sins [among the Jews], but in the beginning he thought that there was not among them the sin of the tongue, so that, as a result, the Satan could not condemn. [As Chazal have said (Vayikra Rabbah 26): "The generation of Achav, even though they were guilty of idolatry, would go to war and win, because there was no lashon hara among them. The generation of David {in the days of Saul), though there were among them children who were versed in the forty-nine facets of the Torah, would go to war and fall, because there was lashon hara among them"] But when Moses saw that there was lashon hara among them, he said: "In truth, the thing has become known," saying as it were: "In truth, now the "known" thing, the sin of idolatry, has become known above and has been publicized, and all of their sins are heaped up upon them, for which reason they are so greatly smitten.

And from all this a man can reflect on how careful he must be in guarding against this sin, that he not harm himself, [for when he speaks lashon hara against his friend, he is punished measure for measure, being spoken against above (as Rabbeinu Chaim Vital of blessed memory wrote in Sha'ar Hakedushah: "When you mention the evil of your friend, they will relate your sins")], and that he not harm the entire world, as mentioned above in the name of the holy Zohar.

We find in the Torah that if one stole from his friend, his amendment is to return the stolen object to its owner, and if he grieved or shamed him, to conciliate him and be forgiven by him. But one who habituates himself to this sin [lashon hara] certainly stirs up the Great Adversary to condemn the world. Who knows how many were impoverished because of him [the speaker] and how many died because of him? And though by the laws of man he cannot be punished for this, still, by the laws of Heaven, even though this is gramma [(an act of indirect causation)], he is not absolved of this. Therefore, one who heeds his soul should take great heed of this.