"as Jacob": as Jacob their father blessed them, viz. (Bereshith 48:21) "And G-d will be with you and He will return you to the land of your fathers."
"to a land of corn and wine": as Isaac their father blessed them, viz.
(Bereshith 27:28) "And may G-d give you of the dew of the heavens, etc." "His heavens, too, shall drip dew," as in (Isaiah 45:8) "Let the heavens pour from above and the heights drip righteousness."
(Ibid. 29) "Happy are you, O Israel": Israel says (Shemoth 15:11) "Who is like You among the mighty, O L-rd," and the Holy Spirit responds "Happy are you, O Israel! Who is like you?" All of Israel gathered unto Moses and said to him: "Moses, our teacher, tell us what good the Holy One Blessed be He has in store for us in the world to come." He will answer "I don't know what to tell you" — Happy are you in what is readied for you!" An analogy: A man engages a pedagogue for his son, taking him (the pedagogue) around (his estate) and telling him "All of these trees are yours! All of these grapevines are yours! All of these olive trees are yours!" When he tires of showing him, he says to him "I don't know what more to tell you — Happy are you in what is in store for you!" Thus, Moses to Israel: "I don't know what to tell you — Happy are you in what is in store for you — (Psalms 31:20) 'How vast is Your good that You have stored away for those who fear You.'"