I truly appreciated this post by Eve Levavi Feinstein that leads the reader through the many possible interpretations of the commandment in Exodus 22 for Israelites to offer their firstborn sons to God. As Dr. Feinstein notes, it is not at all obvious what this commandment originally meant for Israelites to do, and the Bible itself offers support for a number of different possibilities. She writes,
In the end, the biblical evidence does not point to a single conclusive interpretation of the law in Mishpatim. On one hand, it may express a requirement (albeit aspirational) that every Israelite family sacrifice its firstborn son. While it is difficult to accept that the Torah commands the ritual slaughter of children, we can at least see in the commandment’s development an attempt to modify a bad law (as Ezekiel put it) by requiring monetary redemption in place of actual sacrifice (Exodus 34:20).
If, on the other hand, what the law required was service at a sanctuary, it calls for an expansion of our understanding of sacrifice in biblical thought. Indeed, the very plausibility of this interpretation — and the fact of its apparent acceptance by P — argues for a view of sacrifice that is not centrally about slaughter but is equally, if not more, about the act of giving.
In either understanding, the law in Mishpatim expresses the idea that the first of all life properly belongs to God. Underlying its cryptic and challenging mandate we can detect a conviction that every birth, human or animal, is a gift from God, which is to be recognized through a partial, symbolic return of life to its Maker.