Neilah
Zera Kodesh (Erev Yom Kippur) writes that נעילה is from the words ה"י נעל, which can be translated as, "Locked with Hashem." This means during Neilah, each person is alone with Hashem. No one else is there, and at this intimate moment, we plead and pray before Hashem.
Every year, the Satmer Rebbe zt'l would go to the kever of Rebbe Eizikel Kaliver on the 7th of Adar. He would always go to the kever at the last moments of the day, before nightfall. One year, he arrived in Kaliv already in the morning, but he nevertheless waited until nighttime to go to the kever. His gabbai asked him why he didn't go earlier to the kever. The Satmer Rebbe replied, "In a market, it is known that the best deals are had moments before the market closes." He meant that the greatest rachamim is at the last moments of the yahrtzeit, and the same applies to Yom Kippur.
