The Torah, “Exodus,” (Mishpatim), 22:28 – 22:29: Your fullness offering and your heave offering you shall not delay; the firstborn of your sons you shall give Me. So shall you do with your cattle and with your sheep: seven days it shall be with its mother, on the eighth day you may give it to Me.
In the past families had many children and the firstborn received special training: They were taught and prepared for their future life. Giving the firstborn to the Creator means to dedicate him with the intention of yearning for the Creator. The firstborn was given to the Levites and the priests that served all over the country in teaching the people, in administration, etc. Thus there was a need to serve and to provide for them so that they would be able to serve and provide for the people. It is a kind of political order.
They were doctors, judges, teachers, and educators, the sector that served the people. So every family gave the Levites and the priests a tithe or the firstborn so that they could live on and teach and educate the people. They had no property of their own.
What was so good about that? They couldn’t accumulate capital and a fortune. Can you imagine the current civil workers having no property of their own, living on only what they receive from the people? Not bad!
From KabTV’s “Secrets of the Eternal Book” 5/27/13