The World to Come is a place where we can comprehend God, and the greatest punishment possible is being denied this experience. There is nothing like this reward among the pleasures of the physical world.

The World to Come is eternal, spiritual life, reserved for the righteous:

The good that awaits the righteous is life in the World to Come. This is life without death, and good without evil…. The reward of the righteous is that they will receive this sweetness and live with this goodness. The punishment of the wicked is that they will not receive this life [in the World to Come]; rather, they will be cut off [they will cease to exist] and will die. Anyone who does not merit this life is truly dead; such a person does not experience eternal life, but is cut off due to his wickedness and ceases to exist, as happens to an animal.

In the World to Come there are no bodies or physical pleasures; rather, there is spiritual understanding and insight:

In the World to Come there are no bodies or physical forms, only the souls of the righteous, just like the ministering angels, who do not have bodies. Since there are no bodies, there is no food or drink, nor anything else that human bodies require in this world, and no physical experiences occur there, such as sitting, standing, sleeping, death, sadness, and laughter. The Sages said, “In the World to Come there is no eating, drinking, or sexual intercourse. Rather, the righteous sit with their crowns upon their heads, basking in the radiance of the Shekhina” (Berachot 17a)…What does “basking in the radiance of the Shekhina” mean? It means that they grasp the truth of the Holy One, blessed be He, in a way that they were unable to when they were in the darkness of the lowly body.

The worst punishment is for a soul to be denied existence in the World to Come:

The greatest of all retribution is the soul being cut off, not meriting that life [in the World to Come]…This loss is what the prophets described metaphorically as “the pit of destruction” (Psalms 55:24), “oblivion” (Psalms 88:12), “inferno” (Isaiah 30:33), and “leech” (Proverbs 30:15). Terms of total destruction are used to refer to it, for it is a destruction without subsequent revival, and a loss that can never be restored.

Fools believe that the reward for performing mitzvot is physical pleasure:

This [reward of] goodness must not be regarded lightly. You should not imagine that, when a person lives entirely in the way of truth, there is no reward for their mitzvot, other than eating and drinking good food, engaging in sexual intercourse with beautiful people, wearing embroidered garments and those made of linen, living in dwellings made of ivory, and using vessels of silver and gold.… Wise and understanding people know that all these things are empty and worthless. They give great pleasure in this world only because we have bodies, and these are all physical needs. The soul desires them only because of the body’s needs, so that its desires will be fulfilled and it will remain healthy. Once there is no body, all these things will be worthless.

There is no way that we, in this world, can truly comprehend the essence of life in the World to Come:

With regard to the tremendous good that the soul will experience in the World to Come, there is no way to grasp it in this world, as in this world we know only the pleasures of the body, which are what we desire. But that good [of the World to Come] is exceedingly great and cannot be compared to the good of this world except by way of metaphor. It is impossible to truly compare the spiritual good of the World to Come to the physical good of this world, e.g., food and drink, for the good [of the World to Come] is immeasurably greater; it is incomparable and inconceivable.

It is called the World to Come because we enter it after life in this world:

The Sages did not use the expression, “World to Come,” to imply that it does not currently exist, or that this world is going to be destroyed and then that world will emerge. This is not the case since it does exist currently…They called it the World to Come because that life [in the World to Come] comes to an individual after life in this world, where we exist with both a body and a soul, and where everyone must live first. (Rambam, Mishneh Torah, Hilkhot Teshuva 8:1–6)

Further reading: For the stages of the soul’s departure from this world, see above, p. 26.