Abstinence is probably the most demanding condition for spiritual
excellence, since at bottom we all tend to indulge while abstinence
demands that we withhold. It also asks us to hone our allegiances and
declare which we favor: heavenly or earthly delights (of course the Torah
allows for both at the same time, but we're talking about *favoring* one
over the other).
The assumption is that since we'd learned all we had in our introspections
about what truly matters and what doesn't, about what we already have and
what we can do without, that we'd be more inclined by now to abstain from
some earthly things than we'd thought we could. And indeed, the wise
reader will come to that point, we're told, and will worship more deeply
and be better off both spiritually and materially as a consequence.
We'll be explaining the difference between "conventional" abstinence and
the kind that the Torah requires of us, and we'll examine the various
sorts of abstainers, the criteria for beneficial and appropriate
abstinence, how the Torah and the Books of the Prophets depict abstinence,
and we'll discover the difference between the way our ancestors abstained
from things and how we're to abstain.