The reason for "Happiness in the afflictions" of the body is that they are a great and potent favour for the sinning soul, to cleanse it in This World and to redeem it from purification in the next. (This is particularly true in our generations, when it is not possible to fast in accordance with the prescriptions in the penances of the Ari, fasts imperative for the cleansing of the soul, to rescue it from cleansing in Gehinnom.)

Nachmanides, in his Introduction to the Commentary on Job, writes that even the sufferings of Job for seventy years have absolutely no comparison to the suffering of a soul even briefly in Gehinnom, for fire is one part of sixty... It is only that the world is built by kindness, and through mild suffering in This World one is saved from severe judgments in the Coming World.

The movement of a shadow on earth of a few inches equals the sun's movement in the heaven of thousands of miles... Infinitely more so is this true in the parallel, in the descent of the worlds, from the most exalted heights until this physical world. We see this in the Zohar's comments on the subject of the elevation of the higher worlds as a result of the initiative taken by man below. The Zohar describes the effects of the offering of one fowl, a dove or pigeon, or a handful of meal, on the altar. Such are the effects of all the mitzvot of performance, as known from the Ari.

This too is our Sages' comment on the verse, "Sanctify yourselves and you shall be holy"— man sanctifies himself only a little below, and he becomes sanctified in great measure from above... (It was noted above in reference to "Who sanctified us with His commandments..." that Israel's sanctification through mitzvot is bound up with the Infinite, that Encompasses all worlds ...)

Precisely so is it in reference to reward and punishment, as our Sages say, "The reward of a mitzvah is a mitzvah ..." as discussed elsewhere. This knowledge is elementary to the understanding, and those with intelligence in this matter will discover good.