Bereishit Rabbah
... Another explanation. “…of the dew of the heavens…” (Genesis 27:28) this refers to Zion, as it says “As the dew of Hermon which runs down on the mountains of Zion…” (133:3) “…and of the fatness of the earth…” (Genesis 27:28) refers to the offerings, “grain” refers to the first-fruits, “wine” to the libations…