We are told that Shabbat is "a taste of the World-to-Come," an intimation of the time when the world will know no evil and G‑d's presence will be manifest in the world. The tranquility of Shabbat is but a taste of true peace, the vision of truth provided by Shabbat an allusion to the expression of real truth, the experience of G‑dliness still incomplete. That is the World-to-Come, everything of which Shabbat provides a taste, called by the medrash, "A day [time] that is all Shabbat." The freedom we experience on Shabbat is a suggestion of the time in which we will be completely free; free of exile, free of evil within ourselves, and free of evil in the world.

We are also told that "if you kindle the lights of Shabbat, I will show you the lights of Zion," so that when Jews the world over kindle the candles and observe Shabbat, G‑d will show us the light of the redemption.

The connection is not arbitrary. And it's not either a sort of reward for our good deeds. Rather, it's a statement of the nature of our existence. For when we kindle a candle for Shabbat, we add light not just to our homes and to our lives, but to the whole world, and when we transform our reality by including Shabbat in our lives, we transform the world and bring it closer to its reality as a place where only goodness can endure.

And when enough of us experience this taste of redemption, the very fabric of our world will be changed as it becomes filled with the light of our Shabbat candles, and our slice of Shabbat will expand into an era of Shabbat for all of humanity.