Exodus 9:8

מלא חפניכם HANDFULS (more lit., as much as will fill your fists), old French joincheiz; Engl, double-handfuls. פיח הכבשן SOOT OF THE FURNACE — the word פיח denotes a thing which is blown away (נפוח) from coals that have become extinguished after being burnt in a furnace; in old French oulvis. פיח is derived from a root that signifies blowing, and it so called because the wind blows it about and scatters it abroad. וזרקו משה AND LET MOSES THREW IT — Since anything which is thrown with force must be thrown with one hand only, there were here several miracles: one, that Moses’ closed fingers (קמץ) held as much as would fill his two fists and those of Aaron, and another, that this dust spread itself over the entire land of Egypt (Midrash Tanchuma, Vaera 14; Exodus Rabbah 11:8).

וַיֹּ֣אמֶר יְהֹוָה֮ אֶל־מֹשֶׁ֣ה וְאֶֽל־אַהֲרֹן֒ קְח֤וּ לָכֶם֙ מְלֹ֣א חׇפְנֵיכֶ֔ם פִּ֖יחַ כִּבְשָׁ֑ן וּזְרָק֥וֹ מֹשֶׁ֛ה הַשָּׁמַ֖יְמָה לְעֵינֵ֥י פַרְעֹֽה׃

And the Lord said to Moshe and to Aharon, Take for yourselves handfuls of soot of the furnace, and let Moshe sprinkle it heaven- wards in the sight of Par῾o.