The Mekhilta DeRabbi Yishmael addresses a practical legal question arising from (Exodus 13:13): "Every human first-born among your sons shall you redeem." The commandment to redeem the first-born son, known as pidyon haben, is one of the Torah's most distinctive rituals. But the Mekhilta identifies an ambiguity in the verse that required careful rabbinic interpretation.
The question is this: what happens if a man has first-born sons from five different wives? Each wife's first son is her first-born. But is the father obligated to redeem only his own first first-born, or must he redeem each wife's first-born child?
The Mekhilta finds the answer in the emphatic language of the verse itself: "Every human first-born among your sons shall you redeem." The word "every" is the key. It does not say "your first-born son" in the singular. It says "every human first-born among your sons," using inclusive language that encompasses multiple first-borns from multiple mothers.
This means that a man with five wives who each bear him a first son must perform the pidyon haben ceremony five separate times, paying the required five silver shekels to a kohen (priest) for each first-born child. The obligation follows the mother, not the father. Each woman's first child to open her womb triggers the commandment independently.
This ruling has practical implications that extend beyond polygamous households. Even in cases of remarriage after divorce or widowhood, if a man's second wife bears her own first-born son, the father must redeem that child regardless of how many sons he already has from his first marriage. The word "every" in the Torah's formulation ensures that no first-born goes unredeemed, no matter how complex the family structure.