Tuesday marks the 9th of Av, the fast that commemorates the destruction of both Temples in Jerusalem. The Talmud asks, “Why was the Second Temple destroyed?” The famous explanation: “Because of sinat hinam, senseless hatred of one Jew for another.”

Almost two millennia later, and sinat hinam remains the biggest challenge to world Jewry today. The expression Klal Yisrael – literally, “All of Israel” – encapsulates the notion of a shared destiny among all Jews, no matter what their denomination or geography. While the old adage, “two Jews, three opinions” is a trait we own with pride, when those opinions are turned into weapons against the “other” in our own community, the delicate tapestry that makes up Klal Yisrael begins to unravel.

This Jewish infighting is manifest both in Israel — where discourse is famously fiery – and in the Diaspora – and certainly between the two.

The last Israeli elections focused heavily on contentious issues that divided the country, including the monopoly of the Chief Rabbinate on religious affairs as well as the controversy surrounding ultra-Orthodox enlistment. The “Women of the Wall” episode sparked divisiveness both within Israel and amongst the Diaspora. Certain behaviors that occur amongst the Jewish community in Israel – whether spitting or throwing trash and chairs or comparing a politician to Hitler – is so beyond the realm of acceptable discourse that we are compelled to confront these incidents before their grip becomes suffocating. After all, is this bitter, antagonistic environment one in which we want to be raising our children?

Diaspora Jewry has also been mired in vociferous disagreements on how to tackle such core issues as inclusiveness and gender equality. Other contentious issues such as patrilineal descent, conversion, Jewish leadership roles, and even the nature of criticism towards Israel, all threaten to render huge cleaves within our global community.

The American Jewish approach to these issues has always been multifarious, and rightly so. Yet, while debate, disagreement and dissatisfaction are essential elements of who we are, going back to Talmudic dialectic and even to the contentiousness of the “stiff necked” Israelites, diversity of opinion can only serve the greater good in a climate of unity.

So how do we create a dynamic that is more conducive to the value of “kol Yisrael areivim ze lazeh” – all Jews are responsible for each other?

The prophet Zekharia declared that the 9th of Av (together with all fasts related to the destruction of the Temples) will be transformed into a day that “shall be joy to the House of Judah” full of “gladness and cheerful feasts.”

When will this day of mourning turn into a day of celebration? When Klal Yisrael finally gives up sinat hinam and champions ahavat hinam – unconditional love.

It will happen when the Jewish people grapple with – but also celebrate – our differences; when divergence doesn’t overshadow our shared destiny, when respect is valued as much as religiosity.

So, on this day of historical mourning, let us recommit ourselves to learning from our mistakes and not repeating them.

How?

Much like learning a language, acceptance, love and understanding are learned easiest when learned at a young age and through direct experiences.

Involving our youth in communities like Jewish summer camps and youth groups teaches them about acceptance of the ‘other,’ based on cooperation, dialogue, and mutual respect. Sending our teens on Israel programs, both short and long, builds personal relationships between the Diaspora and Israel as well as increased understanding. Service projects for Jewish teens in communities with different socio-economic makeups not only teaches acceptance of the ‘other,’ but also engenders acceptance of the ‘other’ within our own community. Intra-generational programs where children, their parents and grandparents come together in a fun and meaningful environment create core building blocks for acceptance, since – like charity – tolerance also begins at home. These experiences don’t just ‘happen’ by themselves – they are carefully designed with a group process and cohesiveness in mind in order to navigate disparate voices towards a common end. Neglecting the importance of these experiences is enabling sinat hanim, a sin, according to the Talmud, that is equal to the three cardinal sins of idol worship, murder and sexual depravity.

It is time to ensure that the future of the Jewish people is no longer marred with the heinous transgression of hatred and to redouble our efforts to educate our children that “the wise person is one who learns from everyone.”

To ensure that we avoid the path ascribed to the 9th of Av, we must act now – by creating meaningful, personal encounters with “others” – Jews and non-Jews – to discover the fundamental ties that we as Klal Yisrael all share. Like all important things in life, getting there requires hard work, creativity and an abundance of patience.

So yes: two Jews, three opinions… but still, one people.