“The classical explanation for breaking a glass at the end of the wedding is to recall the destruction of Jerusalem. As the glass is broken, everyone screams out Mazel Tov! There is something peculiar, not only about recalling an historic tragedy at that exact moment, but also shouting for joy just as it is recalled.
Yet the message is the same as bitter herbs on Passover. We do not only eat bitter herbs, we make a blessing over them. Then we dip them into haroset, which is sweet. The duality of life is symbolized by the historical memory wrapped in a wedding, and the bitter herb mixed with the haroset. Bitterness is not incidental and not fleeting but it is also not final. In defiance of hundreds of years of slavery (bitter herbs) or national catastrophe (the broken glass) we affirm the essential goodness of life that can be so painful.
It is tricky to be optimistic without being simultaneously in denial. Judaism manages the delicate balancing act: pain is real, even at our most celebratory moments. But final victory belongs to the sweetness, the embrace, the promise that one day all weeping will give way to joy.”
-Rabbi David Wolpe