CONCERNING MAN'S DUTY IN THE WORLD
THE FOUNDATION OF SAINTLINESS and the root of perfection in the service of G-d lies in a man's coming to see clearly and to recognize as a truth the nature of his duty in the world and the end towards which he should direct his vision and his aspiration in all of his labors all the days of his life.
Our Sages of blessed memory have taught us that man was created for the sole purpose of rejoicing in G-d and deriving pleasure from the splendor of His Presence; for this is true joy and the greatest pleasure that can be found. The place where this joy may truly be derived is the World to Come, which was expressly created to provide for it; but the path to the object of our desires is this world, as our Sages of blessed memory have said (Avot 4:21), "This world is like a corridor to the World to Come."…
Therefore, man was placed in this world first - so that by these means, which were provided for him here, he would be able to reach the place which had been prepared for him, the World to Come, there to be sated with the goodness which he acquired through them. As our Sages of blessed memory have said (Eruvin 22a), "Today for their [the mitzvoth's] performance and tomorrow for receiving their reward." …
To summarize, a man was created not for his station in this world, but for his station in the World to Come. It is only that his station in this world is a means towards his station in the World to come, which is the ultimate goal.
The National idea, and the Divine idea.
The National idea is that pride and courage which propels a collection of humans to create a society. It includes the concept of State, but goes beyond that. The Divine idea, on the other hand, is the spirit which moves Man to engage the Infinite. It gives joy and vitalizes the Jewish nation, provides meaning to life, and acts as a light unto the nations. It is the presence of shekhinah within the nation.
These two concepts are completely interdependent. The spirit of the Divine imbues the National with meaning and height, while the National provides bravery, sprit de corps and a proper vessel for the nation's mission. The Jews in the times of Solomon experienced this celestial interaction.
However, even when the nation as a whole dwelled in the Divine idea, individuals engaged in idolatry and other spiritual poisons, to which the surrounding nations lured them. The Divine light was pushed out of individual souls, and unleashed the beast inside. The Divine idea began to rot from within, until all that was left was the National idea. This became so divorced from Godliness, that it became more like the nationalism demonstrated by other nations, and it eventually fell apart. However, as hard as it was to see, the Divine spark rested, deep in the recesses of the nation's psyche, waiting to re-emerge.
In the exile, the National idea was gone. All that was left was for the exiles to pick up the pieces of their Divine spark. However, without the National bond, and with the Jews dispersed and no longer rightly a nation, the individualistic tendencies of this spirituality came to the forefront. The Jew became obsessed with individual salvation and guarantee of personal immortality. The minutiae of law and custom replaced the joy of national experience. This is when the World to Come became such an important concept. Earlier, the Divine light completely outshone these concerns, and a person found natural immortality through his membership in Knesset Yisrael. Now, however, the Divine idea gave way to the new Religious idea, one which focused on the negative, rather than the positive. Both always existed, but the focus had shifted.