תַּהֲר֥וּ חֲשַׁ֖שׁ תֵּ֣לְדוּ קַ֑שׁ רוּחֲכֶ֕ם אֵ֖שׁ תֹּאכַלְכֶֽם׃
Vous avez conçu du chaume, vous enfanterez de la paille: votre souffle est un feu qui vous dévorera.
Rashi on Isaiah
chaff (חֲשַׁשׁ) a kind of chaff, something that is easily ignited.
Ibn Ezra on Isaiah
Ye shall conceive. Assyria is addressed.
Rashi on Isaiah
your breath is fire From your body shall emanate breath of fire and will consume the chaff and the stubble.