+ Positive Mitzvah
A Jew to redeem his first born son from an Israelite woman
“You shall surely redeem the firstborn of man” Bemidbar 18:15
This redemption is for five Selaim (silver coins) or movables equivalent to five selaim
This redemption money is given to the Kohen. The redemption money in entirely non-holy.
If the father of the baby boy is a Kohen or Levi or if his mother is a daughter of a Kohen or a Levi, then redeeming the son is not required.
The time of redemption is after 30 days of the birth.
As it says “Those that are to be redeemed from one month” Bemidbar 18:16
If he has no father he must redeem himself when he grows up.
This applies in all place at all times.