Why does it say "Me'asfav Yochluhu
Rashi: They will eat "Deganech" and drink "Tiroshech" (8). Malbim - we are Osef (gather) grain, and Mekabetz grapes - "Zera Rav Totzi ha'Sadeh u'Me'at Te'esof", "Keramim Tita
Why does it say "v'Hilelu Es Hashem"?
Radak: This hints to Ma'aser Sheni and Neta Revai. "Me'asfav Yochluhu" - the owner eats them. They are Hilulim la'Shem - one says Viduy [Ma'aser] on them, and praises Hashem.
Malbim: This applies to grain. They bless Birkas ha'Mazon on it - "v'Achalta v'Savata u'Verachta" (Devarim 8:10). Grapes do not require the three Brachos of Birkas ha'Mazon.
What is the significance of "b'Chatzros Kodshi"?
Radak: The verse discusses Ma'aser Sheni and Neta Revai. They are eaten "b'Chatzros Kodshi", i.e. in Yerushalayim, within the wall - "Lifnei Hashem Elokecha Tochelenu" (Devarim 12:18). The entire city is called Lifnei Hashem Elokecha. Chatzer includes houses.
Malbim: This refers only to wine, from Kerem Revai, which is eaten in Yerushalayim. They eat grain in their houses.
