וְנָטִ֤יתִי אֶת־יָדִי֙ עֲלֵיהֶ֔ם וְנָתַתִּ֨י אֶת־הָאָ֜רֶץ שְׁמָמָ֤ה וּמְשַׁמָּה֙ מִמִּדְבַּ֣ר דִּבְלָ֔תָה בְּכֹ֖ל מוֹשְׁבֽוֹתֵיהֶ֑ם וְיָדְע֖וּ כִּֽי־אֲנִ֥י יְהוָֽה׃ (פ)
J’étendrai ma main sur eux et je ferai du pays une solitude et une ruine pire que le désert de Diblat, partout où ils seront établis, et ils sauront que je suis l’Éternel."
Ibn Ezra
משען ומשענה. The stay and the staff. Poetically said for every kind of staff. 1The repetition of a noun with or without the variation of its form is often used for כל, all; for instance, איש איש every man, Lev. 15:2, חכם מחכם wise in every respect (Prov. 30:24), שממה ומשמה all kinds of desolation (Ez. 6:14, comp. Job 30:3). The explanation of the figure follows immediately, The whole stay of bread and water.
Rashi
in order that I lay them desolate Heb. אֲשְּׁמֵם. I shall lay them desolate and destroy them. אֲשְּׁמֵם, is an expression of שְּׁמָמָה, desolation. Whoever explains it as an expression of אַשְּׁמָה, guilt, errs, because the ‘aleph’ is not part of the radical.