Post History

Why must there be a contradiction between the seventh day of Passover and the eighth day of Sukkot?

[Pesachim 68b](https://www.sefaria.org/Pesachim.68b.8-10) teaches:

>רבי אליעזר אומר אין לו לאדם ביום טוב אלא או אוכל ושותה או יושב ושונה רבי יהושע אומר חלקהו חציו לאכילה ושתיה וחציו לבית המדרש
>
>R' Eliezer says, "A person on Yom Tov can either eat and drink or sit and learn." R' Yehoshua says, "Split it: half of it for eating and drinking, and half of it for the place of study."

In explaining their dispute, the Gemara continues:

>ואמר רבי יוחנן ושניהם מקרא אחד דרשו כתוב אחד אומר עצרת לה׳ אלהיך וכתוב אחד אומר עצרת תהיה לכם רבי אליעזר סבר או כולו לה׳ או כולו לכם ורבי יהושע סבר חלקהו חציו לה׳ וחציו לכם
>
>And R' Yochanan said, "Both of them expound the same source. One verse says [[Deuteronomy 16:8](https://sefaria.org/Deuteronomy.16.8)], 'A day of restraining for Hashem your G-d,' and one verse says [[Numbers 29:35](https://sefaria.org/Numbers.29.35)], 'A day of restraining it will be for you.' R' Eliezer holds: either all of it for Hashem or all of it for yourselves; and R' Yehoshua holds: split it, half of it for Hashem and half of it for yourselves."

I fail to understand the contradiction that R' Yochanan proposes. The Deuteronomy verse is in the context of the seventh day of Pesach, while the Numbers verse is in the context of Shmini Atzeres. Why not suggest simply that each holiday should be celebrated differently, that (the seventh day of) Pesach should be celebrated as a day for Hashem, while Shmini Atzeres should have an aspect of "for yourselves"? That is, starting with the premise that there must be a contradiction between Pesach and Shmini Atzeres, the dispute between R' Eliezer and R' Yehoshua follows; but I fail to see how the contradiction occurs.

Why does R' Yochanan feel that Shmini Atzeres and Shvi'i Shel Pesach must be celebrated in the same manner?