Created Torah as its antidote. If you engage in Torah-study, you will not be delivered into its hand.”
Regarding this arrangement, one might ask: Okay, talmidei-chachamim are like Yissachar; they study Torah all day long. Thus, they already possess the antidote to the yetzer hara. But what about those who are relegated from above to be like Zevulun? They roam around among the goyim engaging in business activities. At those times, they resemble fish out of water. How are they supposed to combat the yetzer hara who waits in the marketplaces and streets to ambush them and trip them up?
The answer is quite simple. With the money they earn as Yissachars, they should provide for their children, enabling them to learn Torah, and give tzedakah generously to support the Yissachars of the world, whose lives are dedicated to Torah-study and the service of Hashem. Thus, while they are outside dealing with mundane, everyday matters related to Olam HaZeh, their counterpart Yissachar, the pillar of Torah, is sitting in the Beis Midrash studying Torah thanks to them. According to this arrangement, the kedushah of Yissachar’s Torah extends to Zevulun as well and affords him protection from the yetzer hara.
This illuminates for us the profound intent of Yaakov Avinu. He foresaw via his “ruach hakodesh” that the role of Zevulun is to engage in commerce and to provide for Yissachar. This meant that Zevulun would face the spiritual danger of drowning and sinking in the waters of earthly desires and temptations. This prompted Yaakov to formulate the berachah: "זבולון לחוף ימים ישכון"—so that Zevulun would constantly see the waves of the oceans and seas and the imminent danger they pose. For, as we have learned, it is their nature to want to inundate the entire world with their waters. It is only by the grace of HKB”H that they are stopped at the seashores by the boundaries He set for them. This is intended to teach him a vital lesson: Although it is essential for him to engage in commerce and worldly affairs, he should never trespass the boundaries that HKB”H set for him. It is imperative that he designate time for tefilah three times a day and establish fixed times to study Torah.