I've often heard the phrase "In each generation in which the Temple isn't rebuilt, it's as if it was destroyed anew". כל דור שלא נבנה בית המקדש בימיו, כאילו נחרב בימיו.
I'm trying to find the earliest source for this phrase. A search on Sefaria brought six late, mostly chassidish sources:
- Shemiras HaLashon (Chofetz Chaim, early 20th century, quoting Chazal)
- Pri HaAretz  and  (Rabbi Menachem Mendel of Vitebsk, 18th century, quoting Razal)
- Pele Yoetz (Rabbi Eliezer Papo, early 19th century)
- Yismash Moshe (Rabbi Moshe Teitelbaum of Satmar, 20th century)
- Likkutei Halachos (Rabbi Nosson of Breslov, early 19th century)
Subsequently I found:
I found in the Yerushalmi Yoma 1:1 the phrase:
כל דור שאינו נבנה בימיו מעלין עליו כאילו הוא החריבו
Any generation in which [the Temple] was not rebuilt in their days, They consider it upon them as if they destroyed it
This version is much harsher, blaming the generation itself. I'm looking specifically for the earliest source of the softer version quoted above, that it was as if it was destroyed.