Midrash su Deuteronomio 33:25

2) "Then I shall give your rains in their proper times": (but) not the rains of all the lands. How, then, am I to understand (Bereshith 28:14) "And all the families of the earth will bless themselves in you and in your seed"? That there will be plenty in Eretz Yisrael and famine in all the lands. And they will come and buy from you and enrich you with money, as it is written (Bereshith 47:14) "And Yosef gathered in all the money that was found in the land of Egypt and in the land of Canaan for the food that they bought." And (Devarim 33:25) "As your days, your flow" — All of the lands will "flow" money and bring it to Eretz Yisrael.

Variantly: "and you shall gather in your corn, and your wine, and your oil": Eretz Yisrael shall be full of corn, wine, and oil, and (the people of) all the lands will stream (there) to fill it with silver and gold, as it is written (Bereshith 47:14) "And Joseph gathered all the silver, etc." And it is written (Devarim 33:25) "And as your days (of doing the L-rd's will) will be your flow." We are hereby taught that all the lands will stream silver and gold into Eretz Yisrael.