אָ֣ז יִבָּקַ֤ע כַּשַּׁ֙חַר֙ אוֹרֶ֔ךָ וַאֲרֻכָתְךָ֖ מְהֵרָ֣ה תִצְמָ֑ח וְהָלַ֤ךְ לְפָנֶ֙יךָ֙ צִדְקֶ֔ךָ כְּב֥וֹד יְהוָ֖ה יַאַסְפֶֽךָ׃
Kung magkagayon, sisikat ang iyong liwanag na gaya ng bukang-liwayway, at mabilis na sisibol ang iyong paggaling; ang iyong katuwiran ay mangunguna sa iyo, at ang kaluwalhatian ng Walang-Hanggan ang magbabantay sa iyong likuran.
Duties of the Heart
The prophetical books contain clear indications of reward and punishment in the world to come. The following are examples: "For G-d shall bring every work into judgment, with every secret thing, whether it be good or evil" (Koheles 12:14). "And you shall tread down the wicked; for they shall be ashes under the sole of your feet" (Malachi 3:21). "[behold a day is coming, it burns as a furnace and all the wicked shall be as stubble...] then shall you return and discern between the righteous and the wicked, between him that serves G-d and him that serves Him not." (Malachi 3:18). "And they shall go forth and look upon the carcasses of the men that have transgressed against Me; for their worm shall not die. neither shall their fire be quenched, and they shall be an eternal abhorrence unto all flesh" (Yeshaya 66:24). "How great is Your goodness, which You have laid up for them that fear You, which You have wrought for them that trust in You before the children of men" (Tehilim 31:20). "Thus says the L-ord of Hosts, if you will walk in My ways . . .I will give you places to walk among these that stand'" (Zach. 3:7). "Eye has not seen, O G-d, beside You, what He had prepared for him that waits for Him" (Yeshaya 64:3). "And many of them that sleep in the dust of the earth shall awake, some to everlasting life, and some to shame and everlasting contempt" (Daniel 12:2). "Your righteousness shall go before you; the glory of the L-ord shall be your reward" (Yeshaya 58:8). And there are many passages to the same effect, too numerous to mention.
Duties of the Heart
Another reason is that the purpose of reward in Olam Haba is essentially clinging to G-d, and drawing near to His supernal light, as written "your righteousness will go before you, the glory of G-d will gather you in" (Yeshaya 58:8), and "the wise will shine like the radiance of the firmament" (Daniel 12:3), and also, "To bring back his soul from the pit (i.e. Gehinom see below Tov Halevanon), to be enlightened with the light of the living" (Iyov 33:30). And no one can reach there except he who the Creator finds favor in, and the favor of the Creator is the root of the reward, as written "his anger is but a moment, in His favor is life" (Tehilim 30:6). And there are hints in parsha bechukosai that pleasing the Al-mighty [is the greatest reward], this is what is written "My soul will not abhor you" (Vayikra 26:11), and "I will turn to you and be unto you a G-d and you will be unto Me a people" (ibid, 26:9).
Duties of the Heart
But if we examine what there is in the books of the other prophets (besides Moshe Rabeinu) on this matter [which is mentioned explicitly], for example "[And the dust returns to the earth as it was,] and the spirit returns to G-d, Who gave it" (Koheles 12:7), and "I will give you a place among these who stand here" (Zecharia 3:7), and "How great is Your goodness that You have laid away for those who fear You" (Tehilim 31:20), and "no eye has seen O G-d besides you, who prepares for those who wait for Him" (Yeshaya 64:3), "your righteousness shall go before you; the glory of the L-rd shall gather you in" (Yeshaya 58:8). When we study these and many more other similar verses in addition to what our Sages taught us in this, and with what our reason tells us, our souls will be at peace, and will be assured of the inevitability of reward and punishment in the afterlife.