The relationship between God and the children of Israel was defined by a ' covenant '- ברית at Mount Horeb- Sinai. After the sin of the Golden Calf, the covenant was renewed and ratified by means of the blessings- ברכות and the admonition – תוכחה in our parasha – Bechukotai . Lev 26..
A second covenant was made before entering the land of Israel and ratified on Mount Grizim and Ebal.On the last day of his life, in Parashat Netzavim, Moses gathered all the people – old, young, men, women, and children etc. and initiated them for the last time into the covenant of God. The new covenant introduced the concept of collective and mutual responsibility and accountability. People according to their degree of influence on others and the community as a whole would be mutually responsible and accountable for the sins of individuals and benefit from the mitzvoth – good deeds of people. Israel are sureties for one another ישראל ערבים זה בזה -
They would only be accountable for sins which were public or revealed and not accountable for hidden or secret sins about which they had no knowledge.
הַנִּסְתָּרֹת--לַיהוָה, אֱלֹהֵינוּ; וְהַנִּגְלֹת לָנוּ וּלְבָנֵינוּ, עַד-עוֹלָם--לַעֲשׂוֹת, אֶת-כָּל-דִּבְרֵי הַתּוֹרָה הַזֹּאת. The secret things belong to the Lord our God, but the things revealed belong to us and to our children forever, that we may follow all the words of this law. – Dev 29:28 . The mutual or collective responsibility and accountability – ערבות is because the Jewish people are considered like one body or everyone in the same boat indicating that they share a common fate and destiny and impact one on each other. Another source for the principle of collective responsibility is the commandment to protest or rebuke a person so that he does not sin or continue sinning and one also disassociates himself from the sin of the other person. Here we are dealing with open or revealed sins. While people may not be accountable for hidden sins, for sure they have a responsibility to try an influence people to observe God's commandments where ever they are and support them. The word – ערבות = collective responsibility is from the letters ערב which hint that a person should be sweet and attractive to others , involved with them and be caring and have a feeling of responsibility for them.
The principle of mutual responsibility – ערבות is introduced to us by the Sages from the section relating to the curses in our parasha Bechukotai with the words - ' They will stumble over each other ' – implying that they will stumble because of each other , because of each other's sin.
וכשלו איש באחיו, אינו אומר איש באחיו, אלא איש בעון אחיו, מלמד שכל ישראל ערבים זה בזה
The question is asked - why did the Sages choose a verse from the curses which describes Israel in exile, scattered amongst the people of the world. When Moses speaks about the blessings for keeping the covenant he does so collectively – there will be rain in its due season, you in the plural, will have good harvests etc. The Sages could have introduced the concept of collective responsibility – ערבות from the section dealing with blessings so why did they introduce the concept in the context of the curses.
The first answer is that mutual responsibility can characterize a people even if they are scattered in exile and not united in their homeland. This was shown to characterize the Jewish people during the Mendel Beillis trial in Russia where Beillis was accused of a ritual murder, the blood libel. The prosecution tried to incriminate Beillis from the saying of the Sages that ' Israel are called Adam- man, but the nations of the world are not called Adam-man', implying that it was not a problem to murder a non-Jew for religious purposes as they are not considered people. The Rabbis offered a different explanation of the saying-
ישראל קרואים 'אדם' ואין אומות העולם קרואים 'אדם -
Israel is called man in the singular because they display a singular collective responsibility. When one Jew is unjustly accused of murder, they rally around him and support him from all corners of the world. When a non-Jew is accused, only a few people from all over the world identify with his plight.
I suggest a further answer. The Torah seems to be giving good reasons - blessings or curses - why we should take responsibility for others and ensure that they observe the commandments and be loyal to the covenant. But we don't like to encourage people and especially students to be pro-social and generous because of self- interest and selfish reasons. But maybe ' enlightened self -interest ' might be different. When we encourage people to be pro-social, contribute to the community and support people's spiritual growth, everyone benefits both materially and socially. So people have a personal interest in the welfare of others, because they benefit too. Rabbi SR Hirsch explains the verse - and people will stumble ' because ' of each other - וכשלו איש באחיו , that in times of fear and stress, people tend to be concerned only about saving themselves and as a result cooperation suffers and is missing. So even without intention people contribute to the loss of lives. בשעת אימה –כאשר דעתו של אדם נתונה רק להצלת עצמו – תחסר כל שותפות של עשייה ,שלא במתכוון יאבד האחד על ידי חבירו The problem is that self – interest is materialistic and materialism separates and disconnects people. Even if we focus on ' enlightened self- interest, the focus is still on the self. We have to promote ' altruism ', that collective and mutual responsibility = ערבות is a value in itself. The blessing is not a reward for people keeping the covenant and being collectively responsible for each other. The blessings come to support our loyalty to covenant and help us support each other. The curses and hardships come not as a punishment but to challenge the neglect of the covenant and a belief that the only responsibility a person has is for himself and his immediate family.
As parents and educators we have to promote collective responsibility and altruism as a value on its own and not to encourage pro-social behavior using extrinsic motivators, self –interest and not even enlightened self- interest. We want kids to ask – what type of family, classroom, school, community and society do we want. Collective responsibility informs us about the importance of the environment and the system for empowering people. There is a tendency in education to focus on the individual and on promoting personal character such as self- discipline and grit and ignoring the vital role that a supporting and nurturing environment, plays in the lives of children. We see the importance of a sense of belonging, positive friendships and relationships. In a sense, friends have a more powerful influence on children than parents. The Mishna says – buy a friend – invest in friendships – קנה חבר. Kids mirror themselves and reflect using their friends rather than parents or teachers. Parents and teachers are not the standards with which kids measure themselves. When kids have friends from different generations, then older people too, can become a reference point for kids and they begin to relate to the community as a whole and not just their peers or school in a way which reflects collective and mutual responsibility.