Your fellow is your mirror. If your own face is clean, the image you perceive will also be flawless. But should you look upon your fellow man and see a blemish, it is your own imperfection that you are encountering—you are being shown what it is that you must correct within yourself. (Rabbi Israel Baal Shem Tov)
chabad.org
The Noam Elimelech says that the holiness of the parchment we use to write a Torah, Tefillin or Mezuzah is holier than all of the holiness of the letters, because each letter only contains its own holiness, but the parchment has the holiness of the entire Torah, as well as the individual letters. The holiness of the 50th day includes the holiness of the 49 preceding days, because it connects them all together. We count the 49 days in order to reach the 50th. The 50th day is parchment which connects the other 49 days, and therefore is filled with their holiness.
ncsy.org