To what does "v'Amarta" apply?
Malbim: It applies also to verse 10; "Hashmen Lev ha'Am ha'Zeh" is a Ma'amar Musgar (parenthetical comment).
Why does it say "Shim'u Shamo'a"?
Rashi: I tell you to listen, and you do not heed to understand and see miracles that I did for you. You do not put to your heart to know Me.
Radak #1: "Shim'u" and "u'Re'u" are commands. The same applies to "Hashmen" (10). This is Hashem's way - when a sinner wants to sin, Hashem withholds from him the ways of Teshuvah, until he receives his punishment 1 . "Va'Yachazek Hashem Es Lev Pharaoh" (Shemos 9:12), and regarding Sichon "Ki Hiksheh Hashem Elokecha Es Rucho v'Imetz Es Levavo" (Devarim 2:30). It says about Bnei Eli "v'Lo Yishme'u l'Kol Avihem Ki Chafetz Hashem Lahamisam" (Shmuel I, 2:25).
Radak #2: Shim'u" and "u'Re'u" are command forms in place of the prefix to show second person. It is as if it says "Tishme'u
I.e. Hashem commands them to make their hearts fat, in order that they will receive their punishment.
