with the vapor of the mouth

Figuratively: by speech alone. Because of mere idle words (literally: 'vapor of the mouth' means the air of speech that comes out of the mouth).

("The Holy One, blessed be He, said to Moses: Give them an answer! – He said before Him: Master of the Universe, I am afraid lest they burn me with the vapor of their mouths. – He said to him: Take hold of My glorious throne and return them an answer" – Shabbat 88b, and also: "When speech is on the side of good it is called speech and makes an impression above, but when it is not so it is called vapor of the mouth, vanity of vanities" – Shlah, Parashat Vayakhel Pekudei, Torah Or, and also: "There is a vapor that is done upon the earth (Ecclesiastes 8), the meaning of vapor, that is the vapor of the mouth that comes out of the throat... and from the vapor that leaves their mouths, it reaches them as the deeds of the righteous" – R. Nachman of Breslov, Likutei Moharan, Torah 109, and also: "And they are zealous, vengeful, and bear grudges like a serpent, and they are able to burn the whole world with the vapor of their mouths" – Y.L. Peretz, Silent Souls, 94, and also: "You saw how troubled they were," he said to Dar, "and he enveloped me with the vapor of his mouth" – Haim Be'er, Feathers, 79)

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