First Nephi 2:20

And inasmuch as ye shall keep my commandments, ye shall prosper, and shall be led to a land of promise; yea, even a land which I have prepared for you; yea, a land which is choice above all other lands.

“Land of promise” is always a metaphor in the scriptures for exaltation. Prospering materially and temporally is good, but it is not the point of mortality. Spiritual prosperity is what we are after, and exaltation in the celestial kingdom – the true land of promise – is our eternal goal.