Musar zu Schemot 21:11

The land of Israel which is under the constant direct supervision of G–d (Deut. 11,12), is in this respect an allusion to the corresponding ארץ עליונה, "earth of the Celestial Regions" all of which belongs to Israel. This is the meaning of Isaiah 60,21: ועמך כולם צדיקים לעולם יירשו ארץ, "As for your people who are all righteous, they will inherit an earth in another world." The Hereafter (the rejuvenated planet earth), [alluded to in פרשת בהר as the seventh year, Ed] is called שבת, as opposed to the six years, i.e. the 6,000 years of mankind's physical existence on this earth as it is now.