Our parasha opens with the laws of Shemita, but only after the seemingly superfluous declaration that the parasha was given on Mt. Sinai.

Following the Midrash, Rashi says that we learn from here that just as all the general rules and minute details of Shemita were ordained on Mt. Sinai, so too all the rules and details of the other commandments were given there as well.
Fully accepting this explanation, the Or HaChayyim HaKadosh points out that we must still understand why this general lesson was taught specifically in the context of the mitzvah of Shemita. He explains that the Torah wished to stress the linkage between Sinai and the gift of the Land of Israel, as the passage opens: "... When you come to the Land which I am giving you, then shall the land keep a sabbath to the Lord."
The promise of the land is anchored in the very story of creation (see Rashi's first comment on the Torah), and yet it is only via Sinai that this promise is to be fulfilled.
To this powerful message, I would like to add the following observation:
The Torah speaks here in the present tense: "the Land which I am giving you"- God's gift is an ongoing one.
God is always ready and prepared to hand us His land, provided that we are there , ready to receive it, actively taking part in its redemption.
When we receive e-mail messages notifying us that we have won millions, we instinctively press 'delete' and move on. This Shabbat as we read of God's promise of Eretz Yisrael we must not do the same! For if God sees that we are rejecting his gift, might He not pass it on to another nation?!