In this aliyah, the Aibershter establishes the sacred gifts and responsibilities of the Levi'im. Having chosen them for the holy avodah of the Mishkan, Hashem commands that the Bnei Yisrael must no longer approach the Tent of Meeting to perform the service, lest they incur a capital sin. Instead, the Levi'im alone will carry out this avodah, and in return for their service, they are given the Ma'aser Rishon (the first tithe) from the harvest of the rest of the nation, as they do not receive a physical inheritance in the Land of Israel.
The aliyah details the specific halachos of Ma'aser Rishon and Terumas Ma'aser. When the Levi'im receive their tithes from the Bnei Yisrael, they are commanded to separate a tenth of that tithe—the very best and holiest portion—as Terumas Ma'aser to be given to Aaron the Kohen. Once this holy portion is properly separated, the remaining tithe is fully permitted to the Levi'im and their households to be eaten anywhere as their rightful wage, warning them that failing to separate the best portion first would profane the sacred donations and bring about the punishment of death.
In this parshah, the Torah teaches us a beautiful and profound lesson about the nature of our avodah and how we view our livelihood. The Leviim do not receive a physical portion of land in Eretz Yisrael. Instead, their entire sustenance comes from the tithes, the ma'aser, given to them by the rest of Bnei Yisrael. Yet, the Torah emphasizes that this is not charity; it is their direct "sachar," their rightful wage from the Aibershter in return for their sacred service in the Mishkan.
But the lesson goes deeper. Even though the Leviim receive this holy gift directly from the hands of their fellow Jews, they are not exempt from the mitzvah of giving. Before they can enjoy their portion, they must separate "ma'aser min hama'aser", a tenth of the tenth, and give the very best, the "chelev," to Aaron the Kohen. The Torah is teaching us that no matter who we are, and no matter how holy our work is, we are never just receivers. We must always be givers, and when we give, we must give from our very best.
Sometimes a person thinks, "I am struggling to make ends meet," or "My work is entirely spiritual, so others should support me." The Torah tells the Levi: even your livelihood, which is already a tithe, must be tithed. When we take the first and best portion of whatever Hashem sends us, our time, our energy, or our money, and dedicate it back to Him, we elevate everything else we possess. It turns our physical sustenance into something holy, as the Torah says, "it shall be accounted to you as the grain of the threshing floor."
Today, look at whatever bounty Hashem has blessed you with, whether it is your income, your wisdom, or your time. Before you use it for yourself, dedicate the very first and best few minutes, or the first portion of your resources, to a holy cause or to helping another Yid.