The Torah commands in the Book of Shemot (13:13), “Ve’chol Peter Hamor Tifdeh Be’seh” – that every firstborn donkey must be “redeemed” by giving a sheep. This means that if a person owns a female donkey, and its firstborn is male, then the owner must give a sheep to a Kohen, in exchange for which he receives rights to keep his firstborn donkey. The donkey is then considered the property of its owner, and the sheep becomes the property of the Kohen. Both the donkey and the sheep are Hulin – regular animals, that have not been consecrated – and thus they may be used for any purpose the respective owners wish. This obligation of Pidyon Peter Hamor (redeeming the firstborn donkey) rests only upon a Yisrael; a Kohen or Levi who has a firstborn male donkey is not obligated to redeem it. The donkey must be redeemed regardless of whether the owner is a man or a woman. This command applies at all times, even nowadays, when we do not have the Bet Ha’mikdash. If the donkey’s owner does not own a sheep, he may redeem the donkey by paying a Kohen the value of a sheep. The Gemara in Masechet Bechorot (11) teaches that a generous owner pays a Kohen a Sela; a stingy owner pays just three Zuzim; and an average owner pays a half-Sela. The redemption must be paid within thirty days of the donkey’s birth. This Misva marks the only instance where a non-kosher animal is given a special status. The firstborn males of kosher species are considered sacred and are brought as a sacrifice, but firstborn non-kosher animals have no special designation, the lone exception being the donkey. The Sefer Ha’hinuch explains that a sheep is paid for the redemption of a donkey to commemoration the great miracle of Yesi’at Misrayim (the Exodus from Egypt), when G-d killed the firstborn Egyptians. Furthermore, Beneh Yisrael are compared to sheep, whereas Egypt is compared to a donkey, and thus a sheep is exchanged for a donkey to show that G-d took Beneh Yisrael out of Egypt to be His treasured nation. As we will see, the Torah commands that one who does not wish to pay a sheep for the redemption of his donkey is required to kill the donkey. The Minhat Hinuch clarifies that although the Torah offers this option, nevertheless, redeeming the donkey is preferable to killing it, and thus one who chooses the second option, and kills the donkey instead of redeeming it, is guilty of neglecting the Misva of Pidyon Peter Hamor. However, the Minhat Hinuch adds, Bet Din would not coerce a person to redeem the donkey instead of killing it. When Bet Din has the authority to enforce Torah law, it would use coercive measures to force people to fulfill the Torah’s commands. In this instance, however, since the Torah offers the option of killing the donkey instead of redeeming it, Bet Din cannot force the donkey’s owner to redeem it, even though this is what he is supposed to do. The Minhat Hinuch draws a comparison to the Misva of Yibum – the obligation to marry one’s deceased brother’s wife if the brother had died without offspring. The Torah offers the option of performing the Halisa ritual in place of Yibum, though the obligation is to marry the widow – just as a firstborn donkey’s owner is obligated to redeem the animal instead of killing it. Since the Torah presented this option, Bet Din is not authorized to coerce the brother to marry the widow instead of performing Halisa, even though he is obligated to marry her. (Nowadays, Halisa is always performed in such a case, for reasons which lie beyond the scope of our discussion.)