Zebulun, the son of Jacob and Leah, tenth of the Twelve Tribes, was born on the 7th of Tishrei. The tribe of Zebulun is known for their success in sea commerce, and their financial support of the Tribe of Issachar. One of the valuable commodities the tribe of Zebulun harvested in the sea was the chilazon. It was a rare marine creature whose “blood” was used to produce the tekhelet fabric dye.
Zebulun also harvested premium fish from the sea, and manufactured unique white glass from the sand.
Zebulun will dwell on the coast of the seas; he [will be] at the harbor of the ships, and his boundary will be at Zidon. (from the Yaakov’s blessings to his sons, chapter “Vayechi”, Breishit 49:13).
The chassidic teachings explain that Zebulun’s role was to enter the “market” and reveal the sparks of G-dliness hidden within the material world.
In his blessings to bnei Israel before their entrance to the Land of Israel (the year 2488), Moshe Rabbeinu says that Zebulun and Issachar should have a partnership.
And to Zebulun he said: “Rejoice, Zebulun, in your departure (when you go out to trade), and Issachar, in your tents. (from the blessing of Moshe Rabbeinu, chapter “Vezot Hab’rachah”, “Dvarim” 33:18)
Rashi explains: Zebulun will engage in commerce and will share his profits with Issachar. Issachar, in his turn, will devote his time to studying the Torah. Since the merit of Issachar’s Torah study is ascribed to Zebulun, he is mentioned before Issachar, even though Issachar is older.
Sources: “Seder ha-Dorot”’; Yalkut Shimoni, Shemot, remez 162; Megilah 6a.