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
“Every day, the Torah must be new to you.” (Sifrei)
Torah is our life, and life is here and now, forever new.
Which means that for you to be truly alive, the Torah you learn today must touch the core of your soul.
And the same tomorrow. And the next day as well.
To live with Torah is to be forever newly born.