Who will eat butter and honey, and what is the significance of this?
Rashi: The child will eat them, for a Siman that our land will be full of all good.
Radak: The baby, from when he is born. This is connected to "l'Dato Ma'os ba'Ra u'Vachur ba'Tov" - he will open his mouth to eat anything sweet put in front of him, and close his mouth when any bad food is put in front of him.
Radak citing Targum Yonasan: The child will eat them before he will know to detest evil and choose good.
Radak: Disputers say that this refers to one who will be born 400 years later 1 . My father refuted this. The baby is a sign to assuage Achaz, who feared imminent attack of Aram and Efrayim!
Malbim: The child will eat them before he will know to detest evil and choose good. He is a metaphor for the Klal of the nation, just like his name Imanu'el means that Hashem will be with the Klal of the nation. The nation will eat butter and honey when Hashem is with them, even though now Eretz Yehudah is destroyed.
Surely he refers to heretics who explain it to predict the birth of a false Messiah. However, he was born about 600 years later! Perhaps he wrote 400, for it is clear that almost all the years of Bayis Sheni were in between. Or, he wrote 400 to 'hide' to whom he refers. (PF)
What is the meaning of "l'Dato Ma'os ba'Ra u'Vachur ba'Tov"?
Rashi: When he will know to detest evil and choose good.
Radak: "L'Dato" refers both to what came before (eating butter and honey - refer to 7:15:1:2), and what is after (detesting evil and choosing good).
Radak citing Targum Yonasan: Refer to 7:15:1:3.
Radak (16): Detesting evil and choosing good is when he has Da'as to choose, when he begins to speak.
