1) AN EXCHANGE OF A SANCTIFIED ANIMAL
QUESTION: The Gemara quotes a Beraisa which states that when one proclaims that he exchanges his cow for a cow which is Hekdesh, the exchange takes effect and "Hekdesh has the upper hand." This means that Hekdesh receives the value of the most expensive cow, regardless of whether the cow being exchanged is worth more or less than the cow of Hekdesh. Even if it is worth less, the person who makes the pledge must add money to equal the value of the cow of Hekdesh (in addition to the extra Chomesh, fifth, that he must add).
Why does the Kedushah of the Hekdesh animal transfer to the new animal? The law of Temurah (Vayikra 27) clearly teaches that when a person attempts to exchange an animal for an animal of Hekdesh, both animals become Hekdesh. Why is this exchange valid in this case?
(a) Tosfos answers that the concept of Temurah applies only to Korbanos, not to Kodshei Bedek ha'Bayis. The Gemara here refers to an animal consecrated as Hekdesh to Bedek ha'Bayis. Even though the Gemara in Temurah (5b) says that one who consecrates an animal, which is fit to be a Korban, to Bedek ha'Bayis commits a sin, his Hekdesh nevertheless is valid.
However, Tosfos has difficulty with this approach. The Gemara in Temurah (33b) states that whatever is fit for the Mizbe'ach is always designated for the Mizbe'ach. This means that an animal consecrated as Hekdesh for Bedek ha'Bayis becomes consecrated as a Korban and not as Bedek ha'Bayis.
1. Tosfos answers that the animal in fact must become a Korban. When the Gemara says that the exchange works, it means that the animal which is acquired by the person who exchanges his animal for Hekdesh must be sold to be used as a Korban Olah. The seller is allowed to keep the money from the sale for himself.
The AYELES HA'SHACHAR asks that the concept of selling such an animal so that it should be used as a Korban is explicitly stated by the Gemara in Temurah (ibid.). Why does Tosfos not attribute his answer to the Gemara there?
The Ayeles ha'Shachar presents two ways to understand how an animal which attains a degree of Hekdesh must be brought as a Korban. It is possible that once the animal is proclaimed Hekdesh it is considered to have Kedushas Mizbe'ach. Alternatively, the animal does not become sanctified with Kedushas Mizbe'ach, but it becomes obligated to be sold as a Korban. Tosfos here follows the second approach, that the animal must be sold as a Korban but does not have Kedushas Mizbe'ach. Tosfos does not quote his statement from the Gemara in Temurah, so that one not mistakenly understand that the animal actually becomes sanctified with the Kedushah of a Korban Olah, and that when the Gemara in Temurah says that the animal is sold for an Olah it means that the Kedushas Bedek ha'Bayis element of the animal is sold in order that it should be a complete Olah. (The Ayeles ha'Shachar understands that the opinion that the animal actually has Kedushas Olah before it is redeemed is the view of a different Tosfos quoted by the RITVA.)
2. Alternatively, Tosfos explains that the Gemara refers to a case in which the animal had a permanent blemish before it was made Hekdesh. Accordingly, it was never a candidate to be brought as a Korban. Since it was never fit to be a Korban, the Gemara in Temurah (33b) does not apply here. (Y. Montrose)

55b----------------------------------------55b

2) THE RABANAN GAVE "CHIZUK" TO THEIR ENACTMENTS MORE THAN TO THE LAWS OF THE TORAH
QUESTION: The Mishnah states that one who eats Terumas Ma'aser of Demai must pay a Chomesh, an extra fifth. Rava says that Rebbi Elazar (ben Pedas) had difficulty with this law. Did the Chachamim make their laws the same as those of the Torah? Apparently, Rebbi Elazar is bothered why the Rabanan made their enactment as strict as Torah law when they decreed that one who eats Terumas Ma'aser of Demai must pay a Chomesh, just as the Torah requires that a non-Kohen who unintentionally eats Terumah must pay a Chomesh.
The Rishonim have difficulty with this question. The Gemara says in many places that the Rabanan specifically strengthened their enactments, sometimes even by making them more stringent than the laws of the Torah. What was bothering Rebbi Elazar?
ANSWERS:
(a) TOSFOS (DH v'Chi) answers that Rebbi Elazar's question was that, normally, the Rabanan invoke a stringency in order to discourage people from transgressing the decree of the Rabanan. However, the Chomesh instituted by the Torah itself is a stringency which the Rabanan would not have added had the Torah not done so.
Tosfos apparently means that since the Rabanan usually do not apply a fine (when it is not for a preventative measure) for one who transgresses certain laws, whether mid'Oraisa or mid'Rabanan, the Rabanan also should not have instituted a fine for Terumas Ma'aser of Demai.
(b) The RITVA answers that the entire decree of Demai itself a great stringency, since the decree was made only because of the minority of Amei ha'Aretz who do not separate Ma'aser from their produce. Rebbi Elazar therefore was perplexed as to why an additional stringency of Chomesh was added to this decree.
(c) The Ritva writes in the name of TOSFOS that there are other things for which the Torah requires a payment of a Chomesh, and yet the Rabanan did not decree that their correlating laws d'Rabanan should require the payment of a Chomesh. Why is it that in most places the Rabanan did not institute the requirement of a Chomesh like the corresponding Torah law, but for Terumas Ma'aser of Demai they did? This was Rebbi Elazar's question. (Y. Montrose)