There was a story with HaGaon HaTzaddik R’ Zalman Baron zt”l (posek in Yerusholayim, brother of R’ Dovid Baron). A Yid once came to him on motzei Yom Kippur to show him a beautiful mehudardika [stunning] esrog, however, there was one small problem with the esrog, it was chosar [it had some of the flesh missing]. On this particular year, the first day of Succos fell on Shabbos. After realizing that the esrog was chosar, R’ Zalman Baron told the Yid that since the esrog is chosar it’s no good.
The Yid then turned to R’ Baron confused and said, “Chosar?!!! This year the first day of Succos falls on Shabbos, and chosar is only a problem on the first day?”. R’ Zalman Baron all shocked and visibly disturbed turned around and shouted, “DO YOU NOT BELIEVE IN THE COMING OF MOSHIACH? DO YOU NOT EAGERLY AWAIT HIS ARRIVAL EVERY DAY? Speedily the Beis HaMikdosh will be rebuilt, and we will all merit making a berachah on a lulav and esrog on the first day of Succos, even if it falls on Shabbos (see Rambam, Hilchos Lulav 7:16), and if your esrog is chosar it will be pasul [disqualified].”
R' Baron added: An esrog which is chosar is a problem during the remaining days of Succos as well. In the Beis HaMikdosh the chiyuv to take the arbah minim is de’O’raisa all seven days of Succos, therefore, an esrog which his chosar is a problem all seven days of Succos, as we anticipate the arrival of Moshiach every single day. (This story is cited in the sefer Arbas HaMinim HaSholem pg. 404)
