Between Purim and Pesach- Chagei HaGeulah

MISHNA: If the people read the Megilla during the first Adar and subsequently the year was then intercalated by the court and now the following month will be the second Adar, one reads the Megilla again during the second Adar. The Sages formulated a principle: The difference between the first Adar and the second Adar with regard to the mitzvot that are performed during those months is only that the reading of the Megilla and distributing gifts to the poor are performed in the second Adar and not in the first Adar. GEMARA: ...The Gemara asks: If so, whose opinion is taught in the mishna? It is neither the opinion of the anonymous first tanna of the following baraita, nor that of Rabbi Eliezer, son of Rabbi Yosei, nor that of Rabban Shimon ben Gamliel, as it is taught in a baraita: If they read the Megilla during the first Adar and the year was then intercalated, they read it during the second Adar, as all mitzvot that are practiced during the second Adar are practiced in the first Adar, except for the reading of the Megilla. Rabbi Eliezer, son of Rabbi Yosei, says: They do not read it again during the second Adar, as all mitzvot that are practiced during the second Adar are practiced during the first Adar. Once the Megilla was read during the first Adar, one need not read it again during the second Adar. Rabban Shimon ben Gamliel says in the name of Rabbi Yosei: They even read it again during the second Adar, as all mitzvot that are practiced during the second Adar are not practiced during the first Adar. And they all agree with regard to eulogy and with regard to fasting that they are prohibited on the fourteenth and the fifteenth days of this month of the first Adar and on that month of the second Adar... Rabbi Yoḥanan said: And both of them, Rabban Shimon ben Gamliel and Rabbi Eliezer, son of Rabbi Yosei, interpreted the same verse differently, leading them to their conclusions. It is written: “To enjoin upon them that they should keep the fourteenth day of the month of Adar and the fifteenth day of the same, in each and every year” (Esther 9:21). Rabbi Eliezer, son of Rabbi Yosei, maintains: “In each and every year” teaches that Purim must be celebrated the same way each year, even if it is intercalated: Just as each and every year Purim is celebrated during Adar that is adjacent to Shevat, so too here in an intercalated year Purim is celebrated during Adar that is adjacent to Shevat. And Rabban Shimon ben Gamliel maintains: “In each and every year” teaches that just as each and every year Purim is celebrated in Adar that is adjacent to Nisan, so too here, in an intercalated year, Purim is celebrated during Adar that is adjacent to Nisan. The Gemara asks: Granted, according to Rabbi Eliezer, son of Rabbi Yosei, the reason for his opinion is logical, based on the principle that one does not forego performance of the mitzvot; rather, when presented with the opportunity to perform a mitzva, one should do so immediately. However, with regard to Rabban Shimon ben Gamliel, what is the reason for his opinion? Rabbi Tavi said: The reason for the opinion of Rabban Shimon ben Gamliel is that juxtaposing the celebration of one redemption, Purim, to the celebration of another redemption, Passover, is preferable.