The inherent duality (shniyut) within the human being of the yetzer hatov (good inclination) and the yetzer hara (evil inclination)--and a vision of the end of the days of duality ("miketz shnatayim yamim") by experiencing peace and coming to realize the illusory nature of evil. Can we catch a glimpse of this every seventh day on Shabbat?
In memory of my grandmother, Eva Filler, Chava Bracha bat Ben-Tzion Halevi z"l.