In his discussion of the mitzvah of bikkurim in Ein Ayah, Rav Avraham Kook, ztk"l, notes a fascinating contradiction between the nature of the Jewish nation and the Gentiles of the world.
Amongst the Gentiles, he writes, the sophistication of a society is inversely proportional to its agrarian nature. Mainly agrarian societies are generally simpler in nature and development while industrialized ones are the opposite. A quick look around the world confirms this thesis.
However, the Jewish nation is the opposite, Rav Kook states. If one looks through the Torah, the ideal society is one that is almost competely agrarian. The Torah spends a lot of time dealing with agricultural laws. Much of the Temple service (may it be speedily restarted) was based around the products of farms, either animal or vegetable. The prophets wax eloquently of an ideal future in which every Jew sits under his own grape vine and fig tree, happily enjoying the produce of the land.
Rav Kook's belief is that it is the connection to the land and the self-sufficiency that it provides that is the difference here. A farmer is engaged in a profession that can either lead to total kefirah - the strength and might of my hands have got me this here wealth - or an appreciation of the total dependence we must feel on God's mercy and lovingkindness. Therefore the ultimate way to achieve the highest level of spirituality is through the closest connection to the land and the land we most closely connect to, especially when we perform mitzvos and those that apply to it is the land of Israel.
That's why there are few agricultural laws that, d'Oraysa, apply outside the land of Israel. In golus we are not self-sufficient but part of the greater society around us. In Israel the opposite applies. We are to be separate from the other nations but in a way that demonstrates our complete independence from them.
Rav Shimshon Rafael Hirsch, zt"l, in his commentary on Chumash notes that God did not divide our ancestors into 12 tribes by chance but that each tribe had its own unique attributes and talents to bring to the table of nationhood. Unlike other nations that need to interact to function completely ours is one that has everything it needs.
And hence the bikkurim in which we take a symbolic representation of our tie to the land to the Beis HaMikdash and make it clear that we aren't bringing a gift to God. After all, He already has everything. We are stating that everthing we have, including our independence, is from Him.
A happy and healthy Shavuos to one and all.