DEUT1576 A further reason [that Scripture does not elaborate on reward and punishment in the World-to-Come] is that the practice of goodness is of two kinds. One of these is concealed; none but the Creator observes it—e.g., duties of the heart, and the like. The other kind is observable in physical movements and is not concealed from other people. These are the active precepts, performed with the limbs. For the fulfillment of observable duties, the Creator bestows a visible reward in this world. For the fulfillment of inner, hidden duties, He gives a hidden reward, i.e., the reward of the World-to-Come. David therefore referred to it in language that gives expression to this, as he said, “How great is Your good that You have hidden away for those who fear You” (Tehillim 31:20). The manner of punishment--visible and hidden--is like that of reward. Proof of this is God's promise to His people that for visible service there will be visible, immediate reward in this world--as explicitly stated in parashas Im B’chukkosay (Vayikra 26)-- and that for visible, external transgression there will be visible, immediate punishment in this world (ibid.). This is because the people, as a community, are responsible only for external acts, not for what is hidden, as it says: “The hidden things belong to Hashem our God, but those that are revealed belong to us and to our children forever” (Devarim 29:28); “If the people of the community in any way hide their eyes from that person... then I will set My face against that person and his family” (Vayikra 20:4-5). In regard to the inner service and transgression of the heart, however, the Creator, may He exalted, is responsible for requiting them, in this world and the next. That is why Scripture does not elaborate on reward in the World-to-Come.