My Journey Through the Haggadah- Shulchan Orech
The meal is now served. It is customary to start with hard-boiled eggs in or with salt water, various explanations have been made for this custom such as, the roundness of the egg symbolizes life, The salt water has also been connected to the Reed Sea over which we passed on our way out of Egypt to the Promised Land so indirectly reminding us of the Song of the Sea as mentioned earlier.. It has also been compared to the tears shed during our long and difficult Exile.
Hard-boiled eggs are also eaten as a sign of mourning. The first day of Pesach is the same day of the week as is Tisha b'Av (the Ninth of Av), the day of the destruction of both Temples, which we commemorate by a 25 hour fast. We thus connect life and the time of our redemption from Egypt to the day of mourning for the Temple and exile from our Land to the redemption and return to Eretz Yisrael, thus coming a full circle as is the egg. Together with the piece of roasted meat on the Seder dish we also place a roasted egg as a symbol of the Chagiga offering which was brought on every festival, the egg that we eat is perhaps a reminder of that. This roasted egg may now be eaten. If not eaten now it should be eaten at some time and not thrown away as it symbolizes the special festival offering.