Sefer Erchei Yehoshua explains that Shevet Zevulun were merchants who ran businesses. Every business deal is an unknown, as no one can know which deal will bring success and which will not (Pesachim 54B). This is because success really depends on the will of Hashem.
A businessman must be aware of three things. 1. His business must be run in an orderly manner and in a sensible way, rather than haphazardly. 2. He must have a strong spirit. He should not give up and fall to despair if he experiences setbacks. 3. He should rely solely on Hashem for success.
These three ideas are hinted to in the names of Zevulun’s three sons. “Sered” has the same letters as the word “seder”, which means to be organized. “Eilon” can be translated to mean to be strongminded (as in Yechezkel 17:13). “Yachliel” can be read as “yachal l’Keil” – to trust in Hashem. Thus, the three names represent the three important rules of business.
וּבְנֵי זְבֻלוּן סֶרֶ ד וְאֵלוֹן וְיַחְלְאֵל (מו, יד)
And the sons of Zevulun were Sered, Eilon and Yachliel. (46:14)
