Zebulun was the tribe that before all the other tribes devoted itself to commerce, and in this way acted as the agent between Israel and the other nations, selling the products of Palestine to the latter, and foreign wares to the former. Hence the blessing that Moses bestowed upon them. "'Rejoice, Zebulun, in thy going out' on commercial enterprises; at thy instance shall many nations pray upon the sacred mountain of the Temple and offer their sacrifices."
For the people that came into Zebulun's realms on matters of business used to go from thence to Jerusalem to look upon the sanctuary of the Jews, and many of them were converted through the grand impression that the life in the holy city made upon them. Moses furthermore blessed this tribe by giving them an estate by the sea, which might yield them costly fish and the purple shell, and the sand of whose shores might furnish them the material for glass.
The other tribes were therefore dependent upon Zebulun for these articles, which they could not obtain from any one else, for whosoever attempted to rob Zebulun of them, was doomed to bad luck in business. It is the "Sea of Chaifa" also, within Zebulun's territory, where all the treasures of the ocean were brought to shore; for whenever a ship is wrecked at sea, the ocean sends it and its treasures to the sea of Chaifa, where it is hoarded for the pious until the Judgement Day.
One other blessing of Zebulun was that it would always be victorious in battle, whereas the tribe of Issachar, closely bound up with it, was blessed by its distinction in the "tents of learning." For Issachar was "the tribe of scholars and of judges," wherefore Moses blessed them, saying that in "the future time," Israel's great house of instruction as well as the great Sanhedrin would be located in this tribe.