80. " and they said : ` the fire shall not touch us but for a few days '.
say: ` have you taken such a promise from allah,
for he never fails in his promise ?
or do you speak against allah what you do not know ? ' "
81. " yea! whoever earns evil and is encompassed by his sins, these are the
inhabitants of the fire, therein shall they abide forever."
82. " and those who have faith and do deeds of righteousness they are
the inhabitants of paradise, therein shall they abide forever."

commentary :

the qur'an, here, points to one of the false statements of the
jews of which they were proud and that very pride was the origin of
part of their deviation. thus the qur'an responds to it :

" and they said: ` the fire shall not touch us but for a few days.'..."

"... say: ` have you taken such a promise from allah, for he never
fails in his promise? or do you speak against allah what you do not
know?'"

one of the most obvious reasons for the stubbornness and egoism
of this group is their belief in the ` preference of the jewish race over
all other races, and that they are different from other nations, and that
their sinners will have to tolerate the fire only for a few days as their
punishment and, therefore, paradise will be theirs exclusively forever. '

this claim of privileges is not logical in any aspect, because,
before allah, there is no difference between the members of the
human race from the point of rewards or punishments for their deeds.

can they support the expectation to their claim of being
exceptional among nations and therefore receiving special treatment
regarding the general law of penalties by describing something they
have done to deserve it ?

however, the above verse with a logical statement, refuses their
vain imaginations and denotes that their claims depict one of these two
conditions : they should either have taken a particular promise from
allah on the matter that they have not or, they tell lies and
calumniate against him.   

the next verse expresses a common and universal law which
is logical from any point of view. it says:

" yea! whoever earns evil and is encompassed by his sins, these are the
inhabitants of the fire, therein shall they abide forever."

this is a general rule for the sinners belonging to any sect, nation,
in any locality, and at any time.   

there is also a universal, general law for the pious believers,
which the next verse announces :

" and those who have faith and do deeds of righteousness they are
the inhabitants of paradise, therein shall they abide forever." 

explanation :

earning sin

the arabic term /kasb/ and /'iktisab/ both mean: ` to earn or gain
something willingly and consciously '.

earnings are received in return for something done to profit
one's self. this is quite different from merely falling into evil. it is to
selfishly seek one's own gain that is evil. one sin leads to another sin
and thus the conscience of the individual gradually becomes deadened
until sinning becomes natural and normal for that person and he is
totally abandoned to evil and attempts to justify his actions and to deny
that he deserves eternal punishment. the law of cause and effect
works in its natural order in the case of evil as in the case of virtue.
those who devote themselves wholly to evil, must naturally find
themselves beset on every side by the consequent evil effects of the
causative evil factors wrought by the individual. but those who struggle
against evil, however long it may take for them to overcome it, the
inclination towards the evil, cannot be considered equivalent to those
who are out to earn evil. those who struggle to overcome evil hate and
detest it and the individual's earnest and sincere effort to overcome
evil, naturally ends in the triumph of good in the human nature. with this endeavour
of good against evil, the natural consequence of the struggle
strengthens the nobility in the individual's personality. but,
purposefully yeilding to evil with a selfish motive for any selfish gains,
gradually erects a fortress of evil for the individual so that the access of
good becomes more and more difficult and ultimately renders the
individual's approach to any goodness as impossible. as the individual
is totally lost, for all times, to evil, he convicts himself to the perpetual
consequences of the evil all around him for ever.

these kind of people are those who are referred to, later, in
sura 2: 86 which says :

" those are they who have bought the life of this world at the price of
the hereafter, for them the punishment shall not be lightened, nor
shall they be helped."