It is said in the name of the Vilna Gaon that there are only two opportunities among all the 613 mitzvot to physically "enter the mitzvah." One is the opportunity to live in Eretz Yisrael, and the other to be in the succah you have constructed for the Festival of Succot. When you cross the border into the Land of Israel, or walk into the succah, you have "entered" the mitzvah. What is the connection between the succah and the Land of Israel?
Judaism is unique to the world in that Jewish national and religious destinies are identical. The concept of a successful Jewish nation in the Land of Israel is fundamental to our religious destiny. Other nations have holy places and live elsewhere, but for us, our Land is our home, our holy soil and the necessary setting for the ideal fulfillment of mitzvot. Accordingly, the Torah includes both civil and religious law, instructing us in our everyday behavior and our acts of worship, both of which are equally holy. The way we live in the Land is part of our service to