Комментарий к Шмот 5:12

לקשש קש לתבן means TO MAKE A GATHERING, to make a collection FOR the purpose of STRAW for the clay.

V. 12 u. 13. ויפֶץ, aktiv. Pharao hatte, wie so viele spätere Judengesetze, geradezu das Unmögliche gefordert. Wer Stroh sucht, kann keine Ziegeln machen und umgekehrt. Das Volk ergriff daher den einzigen Ausweg, es ließ die einen ausgehen, Stroh suchen, während die andern Ziegel bereiteten. Das wollte aber Pharao nicht. Befehlshaber mussten darauf bestehen, dass jeder täglich sein bisheriges Pensum liefere. — אוץ: zu einem Ziele hindrängen, verwandt mit עוץ, wovon עץ, der Baum, eine Zusammensammlung von Säften und Kräften, die zu einem Ziele in die Höhe getrieben werden, dort die Frucht zu nähren. Im Geiste: Ansammlung von Momenten für ein Ziel: einen Plan fassen, עצה ,עוץ.

ויפץ העם בכל ארץ מצרים, “the people spread out throughout the whole land of Egypt.” We know from Genesis 11,34, that straw was needed to make mud bricks. The search for straw to build the Tower led to G-d punishing those people once, and here, indirectly, it provides G-d with the justification to punish the entire Egyptian nation. Up until the time when Pharaoh issued the decree to withhold straw from the people, only few Egyptians had been directly involved in mistreating them. Now that the Israelites had to forage for straw wherever they could find some. Once they found straw they were beaten by the Egyptians, even by their slave-women. Thus, the entire Egyptian people had become involved in abusing the Jewish people, both men and women. G-d “inspired” Pharaoh to come up with the idea of withholding straw so as to eventually being justified to issue a decree which to some might have been viewed as collective punishment.

קש denotes collecting. Because stubble is something that is strewn about and must be gathered (קושש) it is called קש in other passages.