The schools of Shammai and Hillel for the very first time disagreed regarding a case of Jewish law. This occurred around the turn of the 1st century. In the ensuing generations, the schools argued regarding many different laws, until the law was established according to the teachings of the "House of Hillel" -- with the exception of a few instances. According to tradition, following the arrival of the Moshiach the law will follow the rulings of the House of Shammai.
All throughout, the members of the two schools maintained friendly relations with each other.
After a 12-day sea voyage, the previous Lubavitcher Rebbe, Rabbi Yosef Yitzchak Schneersohn (1880-1950), disembarked at the New York harbor on the 9th of Adar II of 1940, following his miraculous rescue from Nazi-occupied Warsaw.
Links:
Vintage film clip of the Rebbe's arrival in NY, March 19, 1940
More about Rabbi Yosef Yitzchak of Lubavitch
The Baal Shem Tov described life as a spiral staircase, constantly deflecting away from your target in order to attain it.
In Yiddish it’s called a “swindling staircase.” Some wise chassidim have pointed out a connection: Life swindles you into believing you are going in circles when really you are traveling higher each day.
This is the way of every true and lasting ascent: Just as you’re making some progress upward, you see yourself falling away and stumbling in the dark.
If you could see the whole picture, how all things resolve in the end, you would see how those periods of darkness and failure are truly steps higher and yet higher.
They must be. Because we did not create life.
G‑d did. And for Him, there are no failures—