The Mishna teaches: originally the lulav was taken in the Mikdash for 7 days and in the medina for 1 day. The Rambam explains the Mikdash refers to Yerushalaim while others explain it refers to the place of the Beis HaMikdosh. Rashi explains one passuk states ושמחתם לפני ה’ אלקיכם שבעת ימים and another passuk states ולקחתם לכם ביום הראשון. The passuk which states לפני ה’ אלקיכם שבעת ימים refers to taking the lulav in the Mikdash for 7 days, while the other passuk refers to taking the lulav in the medina for 1 day. The Mishna teaches that after the Beis HaMikdosh was destroyed, Rabi Yochanan ben Zakai was mesaken that the lulav should be taken in the medina for 7 days as a remembrance of the Mikdash; when it stood we had the mitzvah for 7 days, and now that the Mikdash is destroyed we are missing this mitzvah.
The Mishna ends, “and the whole day of the waving of the omer it is prohibited to eat chodosh-the new grown grain.” This is it states ממחרת השבת יניפנו הכהן which Onkelos translates “on the day after Yom Tov,” being the second day of Pesach, “the Kohen shall wave it.” The Nesina LaGer explains that Onkelos comes to exclude the opinion of the Tzaddukis who explain literally: the day after Shabbos is when the omer is brought and when the counting starts. The Meshech Chachma explains that the Torah states שבת in reference to the Yom Tov because of the lashon תשביתו annul any leavened bread.
Rashi explains that one passuk states עד עצם היום הזה until the essence of this day you cannot eat any new grain, and another passuk states “עד הביאכם את עומר… until you bring the Omer.” How is this? When the Beis HaMikdosh stood, the korban omer permitted one to eat the new grain. After the churban when the korban omer is not brought, with the day of the 16th of Nissan, one is permitted to eat new grain immediately, as it states עד עצם היום הזה. However, Rebi Yochanan Ben Zakai was mesaken not to eat chodosh until the next day. He was worried that maybe the Beis HaMikdash will be rebuilt and people will say, “last year we ate right away, now too we will eat right away on the 16th of Nissan.” They will forget that when there is a korban one needs to wait until the korban is brought.
Why are these 2 takonos, taking the lulav and eating the chodosh, put together in the Mishna? Tosfos answers that they were enacted together. This can be because both are related to zecher l’churban. Avi Mori shlita answered b’shem the Gerer Rebbe that the Mishna is teaching us a lesson to give us hope and anticipation for the rebuilding of the Beis HaMikdosh. When we take the lulav for 7 days we remember the destruction of the Beis HaMikdosh. We feel sad about the destruction. When we refrain from eating chodosh on the 16th day of Nissan, although we are permitted, it is due to the anticipation of rebuilding the Beis HaMikdash. We hope that the following year the Beis HaMikdosh will be rebuilt and the day alone will not permit eating chodosh, but we will need to wait until after the korban omer is brought. Chazal wanted us to attain the feeling that be’ezras Hashem the Beis HaMikdosh is on its way to being rebuilt soon.
May Hashem bring the Beis HaMikdosh speedily in our days!