I read a chabad sheet which claims (no source) that the main purpose of our religious service is to sanctify the world and not the soul and that this was the mistake of the spies who thought they could grow better if they stayed in the desert living on miracles instead of going to Israel and working the land in mundane activity. Their mistake was that working the land is bringing Godliness into the world and this takes precedence.
could be this is why Chabad chasidim go out all over the world to "sanctify the world".
what does chazal say on this question? looking for sources from the rishonim and before.
update: I don't know what sources Chabad chasidut is referring to, however, I found a source for the concept of sanctifying the world in the Mesilat Yesharim ch.26 (though his interpretation of this midrash is likely based on the kabala) "In this way was all use they made of the things of this world. Since they were clinging to G-d's holiness, blessed be he, behold, it was an elevation and an enhancement for that thing which merited to be of use to a Tzadik. Our sages already referred to the matter of the "stones at the place" which Yaakov took and put under his head..." (Chulin 91b)