ייִדישער מחשבֿה אויף דברים 7:14

Man's life is lived on two planes. He lives privately within the circle of his family, and he lives as a member of society, and must interact with such society in greater or lesser measure. The good he does must be divided then between the good he does within the family circle, and the good he does by contributing to the well being of the community he lives in. He will receive rewards for both his good deeds within the family circle and for the good deeds performed as part of society. To the extent that the good performed as part of society benefits everyone in that society equally, the reward can be collective. Since every member of that society benefitted equally by the input of good, so the reward is the kind that lets everyone benefit equally. Output is commensurate with input. The promise of the Jewish people living together in security, enjoying economic prosperity etc., is a reward for such good deeds performed by dint of being part of a certain society. It is a reward for the physical part of man, but it is allocated on a collective basis. Reward for the spiritual part of the input of everyone involved, is based on the degree of dedication that each person's contribution represents. It is in the nature of things that every individual brings a different degree of kavanah, intent, dedication to the performance of his mitzvoth. That is why our sages say that in the world to come everyone will occupy a level of his own. Since there are many commandments which can be fulfilled only collectively, the building of the temple for instance, the reward for such mitzvot, spiritual though it may be, will be collective. The time for receiving a reward for such mitzvot performed collectively, but not because such mitzvot benefit society (called by our sages yishuv ha-olam), is in the post-messianic era, but on this earth when ideal conditions for physical life will exist. In all cases however, the reward for the degree of the spiritual input by each individual into each mitzvah, regardless if it is of the kind that can only be fulfilled collectively or if it is fulfilled individually, is in olam haba.