"Give to Me the firstborn of your sons"—Numbers 22:28.
We are commanded to "redeem" male firstborn and to give the redemption money – five sela'im – to the priest.
The obligation to redeem the firstborn son lies with the boy's father; the mother is not obligated in this mitzvah.
"The firstborn of a donkey you shall redeem with a lamb"—Exodus 34:20.
We are commanded to redeem a firstborn male donkey with a lamb—which is given to the priest. (Unless the owner wishes to give the priest the monetary value of the donkey.)
Levites are exempt from this mitzvah.
