Based on Sichas Shabbos Vayakhel-Pekudei 5748 - Lubavitcher Rebbe
G-d said to Moshe: "Go down, for your people that you have brought up from the land of Egypt have become corrupt." [Ki Tisa 32:7]
Only "three thousand men" [Ki Tisa 32:28] were actively involved in the sin of the golden calf, which was a comparatively small percentage of the Jewish population of a few million.
Nevertheless, G-d told Moshe to "go down", on which Rashi comments: "Descend from your high position. I gave you this high position only for their sake."
From this we see that a comparatively small number of Jewish people were of great significance, to the extent that they affected Moshe himself, who was not even present.
From the negative, we can also learn the positive: how significant the good deeds of even a small number of people can be for the entire Jewish population.