The Torah relates how each day, no matter how much mann a person would gather, when he would measure it, he would find that he was left with exactly one single portion. However, on erev Shabbos after measuring the mann that had been gathered, they found that they had two portions. Moshe Rabbeinu explained that since the following day was Shabbos no mann would fall, and therefore, they were given a double portion that would last for two days. Nevertheless, there were those among Bnei Yisroel who did not heed Moshe's words and went out on Shabbos to search for mann.
In response to their behavior Hashem tells Moshe, "Until when will you (plural) refuse to observe My commandments (Shemos 16, 28). Rashi, puzzled by Moshe's being included in Hashem's rebuke, explains that as people are wont to say, "When one weeds a field, some cabbage gets uprooted in the process." In other words, although it is the wicked who deserve the rebuke, the righteous are also included.
Rav Wolbe (Shiurei Chumash) asks why this is so. Why are the righteous at fault for the sins of the wicked? He explains that even though it is the wicked who committed the sin, to a certain extent the others are at fault. If the majority is very scrupulous in the observance of a particular mitzvah, it would not be possible for the minority to sin in that area. It is only the laxity in Torah observance of the general populace that allows individuals to sin.
This concept is outlined clearly in the Navi Yehoshua. When Achan took something from the consecrated property of Yericho, Hashem told Yehoshua, "Yisroel has sinned, they have taken from the consecrated property, they have stolen etc." Although it was a single person who was guilty of the above transgressions, the entire Bnei Yisroel were blamed for the misdemeanor. This is because if the rest of Bnei Yisroel would have distanced themselves from stealing to the nth degree, it would not have been possible for any individual to transgress the prohibition to steal. This concept stems from the dictum of Chazal that all Jews are guarantors for each other (Kol Yisroel areivim ze la'ze).
Reb Yisroel Salanter would say that if we strengthen our observance of Shabbos in Lithuania, it will prevent a fellow Jew from desecrating the Shabbos in Paris. A good way to help prevent our brothers from leaving the fold of Judaism - and maybe even bringing those who haven't yet gotten to know their heritage closer - is by strengthening our own observance of Torah and mitzvos. All Jewish people are connected in more ways than meet the eye.