In the Bible and Talmud we find 2 very different approaches to the concept of G-d's reward and punishment. They are typified in the very different ways in which catastrophe is dealt with in the Book of Iyov and the Book of Eicha.

In the Book of Iyov, the righteous and suffering Iyov questions, "How does G-d run the world? Where is His justice?" Iyov is told by G-d that the way G-d executes reward and punishment in this world is beyond human comprehension. The Talmud (in Avot 4) echoes this approach. "It is not within our grasp to understand why righteous people suffer and why evil people prosper." The Talmud in Brachot 7 tells us that Moshe asked G-d, "Show me Your ways," referring specifically to the suffering of the righteous and the success of the wicked. G-d responded that a person in this life can never understand G-d's ways. The limitations, placed on us by our physical existence, restrict the understanding of even the greatest among us. Even Moshe Rabbenu could not understand the great mystery of how G-d's justice operates in this world.

In the Book of Eicha, however, this problem is approached in a very different way. Yes, Yirmiyahu says in Eicha, there is catastrophe, but whenever we find destruction, there must be sin. Sin and destruction go hand in hand and parallel one another.

How should we understand the difference in approach between these two Books of the Bible? How does one resolve G-d's non-answer to Iyov with the clear message of Yirmiyahu that sin causes destruction. An answer is suggested by Sefer Haikkarim in the comparative understanding of the first two sections of the Shema.

The first part of the Shema differs from the second part in several ways. One difference is that the first paragraph, "And you shall love Hashem, your G-d", addresses the individual and is written in the singular, while the second section addresses the nation and is written in the plural. Moreover, the first section of the Shema gives us Mitzvot we must follow but makes no mention of any reward or punishment. The second section of the Shema, does detail for us what will happen if we do not observe the Mitzvot. There an account is given of direct material reward and punishment.

Why is the first section of the Shema in the singular with no mention of reward and punishment while the second section is in the plural and does refer to reward and punishment? The Sefer Haikkarim explains that G-d judges us on 2 levels, as individuals and as part of the nation. On the individual level, G-d judges each person according to his own Mitzvot and Aveirot. However, the reward and punishment for the individual is hidden from us until Olam Haba (the Afterlife). How G-d decides when and how to reward and punish the individual is beyond human comprehension.

This is the philosophy of Iyov. How or why G-d punishes and rewards an individual in this world is a mystery. This is why the promise of material reward and punishment is missing from the first section of Shema, which is addressed to the individual.

However, in addition to judging us as individuals, G-d also judges us as a nation. In the Musaf of Rosh Hashana we speak of two types of judgement, "and of the nations it is said which shall be sentenced to war and which to peace, and the individuals are remembered for life or for death." Not only are individuals judged, but also entire nations are subject to G-d's judgement.

In the case where we are judged as a nation, Sefer Haikkarim tells us that our reward and punishment is not left until the Afterlife. Our reward as a nation is here and now. Thus we can understand the convergence of the plural form of address and the mention of tangible reward and punishment in the second paragraph of the Shema.
This is because it is only on a national level that a physical and visible reward or punishment can occur.