58. " and (remember) when we said, ` enter this city (jerusalem)
and eat of the plentiful therein, wherever you desire,
and enter the gate with humility and ask forgiveness,
we shall forgive you your sins, and give more (the portion of)
those who do good '."
59. " but those who were unjust substituted a saying other than that
which had been spoken unto them, so we sent down upon those who
were unjust a torment from heaven for what they used to pervert."

commentary :
 

the israelites' intensive obstinacy
here we are dealing with another aspect of the life of the
children of israel concerning their entrance in the holy land. it says:
" and (remember) when we said: ` enter this city (jerusalem)..."
the term /qaryah/ in our ordinary speaking usually means: ` a
village or a town ', but in the qur'an it is applied for any place where
people are gathered to live in, whether it is a city, town, or village. the
meaning, here, is jerusalem and the holy land.
then it adds:
"...and eat of the plentiful therein, wherever you desire, ..."
"...and enter the gate with humility and ask forgiveness, ..."
"...we shall forgive you your sins, and give more (the portion of)
those who do good '."
it should be noted that the term /hittah/ philologically means: ` a
putting down ', and, here, it means: ` a petition for the putting down of
a heavy burden of sin from them and asking allah to forgive their
faults.'
the lord commanded the israelites to say that phrase with their
whole hearts and spirits for the purpose of asking, thereby, for the
putting down of their heavy burdens from them,because they needed to
be put down from them before entering the holy land. and, they were
promised that they would be forgiven their sins if they did perform the
the command accordingly. maybe, it is for the same reason that one of
doors of heaven is entitled ` bab-ul-hittah ' (the door of forgiveness).
abu hayyan andulusi says that the objective meaning of /bab/, here, is
one of the doors of jerusalem which is known as ` bab-ul-hittah '. 1
the verse finally proclaims that as for the doers of good, besides
forgiving their sins, there will be endowed some additional bounties and
rewards upon them, too. it says:
"...and give more (the portion of) those who do good."

* * * *
however, allah ordered them to express this phrase sincerely as

a sign of their repentance and request for forgiveness in order to show
their humility unto him. the lord promised them that he would
forgive them their sins if they followed through with the command. in
that case, he would also increase his favour and reward for the good
doers among them along with the forgiveness of their faults.
but, as we know and are acquainted with the stubbornness and
obstinacy of the children of israel, some of them even refused to utter
the phrase and mockingly they said another incongruous word (hinta)
`wheat' instead of it. then, the qur'an says:
" but those who were unjust substituted a saying other than that
which had been spoken unto them, ..."
"...so we sent down upon those who were unjust a torment from heaven
for what they used to pervert."
divine punishment in some form or other awaits those who
unwarrantedly and unjustly change the word of allah and his
covenant, to something other than the original presented to them. 
1 at-tafsir-ul-kashif, vol. 1, p. 109