Variantly: "as the days of the heavens upon the earth": They (the righteous) will live and endure for ever and ever. And thus is it written (Isaiah 66:22) "For as the new heavens and the new earth that I will make will remain before Me, says the L-rd, etc." Now does this not follow a fortiori, viz.: If the heavens and the earth, which were created only for the honor of the righteous, will live and endure forever, how much more so, the righteous themselves, for whose sake the world was created!
R. Yehoshua b. Karchah says (Ibid. 65:22) "For as the days of the tree are the days of My people." "the tree" is Torah, viz. (Proverbs 3:18) "It (Torah) is a tree of life to those who hold fast to it." Now does this not follow a fortiori, viz.: If the Torah, which was created only for the honor of the righteous, lives and endures forever, how much more so, the righteous themselves, for whose sake the Torah was created!