According to the Talmud, when the child forms is in his/her mother’s womb, an Angel teaches him Torah. However, once the child is born to the world, the angel pats him on above his mouth and the child forgets it all – this pat leaves a mark on our top lip.
The newborn child’s mission over the course of his/her life is to relearn all that he had once known. This Midrash is symbolic of the transition from a spiritual world into the physical world that we know it. This Midrash has been suggested as one of the reasons for the name of the Shalom Zochor (Shalom – farewell to zicharon – memory).
The Shalom Zochor is also considered a meal customarily eaten by a mourner, (at which he also eats round foods, like chickpeas). This is because our joy over birth is intermingled with mourning over the baby’s emergence from the spiritual environment of the womb. The baby mourns this loss of Torah, and the community, which shares in his mourning, undertakes to assist him in the process of study and recollection.