213. " (all) mankind was but a single nation, then allah raised prophets
as bearers of good tidings and warners, and he sent down with them
 the book with the truth that it might judge between people on 
that wherein they differed. and none were at odds over it, except those
 very (people) whom it was given unto, after clear arguments had come
 to them, revolting among themselves. so allah guided by his will, 
those who believed regarding that which people had differed 
about the truth. and allah guides whomever he wills to
 the straight path. "

commentary:
it is understood from this verse that human race had a simple and
plain life at the beginning. then, later, after the increase of population
and the appearance of a variety of tastes among them, little by little,
diversities and oppositions arose.

" (all) mankind was but a single nation, ... "

as some islamic traditions indicate, this period has been adapted
to an age before the time of noah (a.s.) when people, with little
information, used to live a simple limited life.

but, sometime later there appeared some conflicts between
individuals when they wanted to gain more and more interests especially
by employing others for reaching the foregoing purposes via them. this
caused that the classes of people and social levels came into existence.

" ... then allah raised prophets as bearers of good tidings and warners, ..."

the necessity of a social life is the existence of a firm and just law
in that society. this law should be able to solve the problems of people.
allah appointed the prophets for solving the problems and removing
the opposition created thereby. he (s.w.t.) sent some heavenly books
down to them, but some arrogant groups consciously stood against the
invitation of the prophets and produced a new conflict, added to their
former ones.

" ... and he sent down with them the book with the truth ... "

in this way, of course, allah led some receptive people to his
guidance with his grace and favour, and left those who, as a result of
envy, jealousy, force, or oppression, resisted against the truth alone to
themselves until they recieve their retribution.

" ... that it might judge between people on that wherein they differed. ..."

explanations:
1- the larger the number of contemporary people in one region
is, the more variety of demands will arise; and, when the life is simpler
and the number of people is smaller, the less the contradictions will be.

2- wherever there lies a dispute, there needs a judge. human
made laws and civilizations are not able to solve the discords of
mankind, because all human groups or individuals usually look for their
own personal needs or demands. the solution of the human problems
should be made up via the path of divine prophets and through the
revealed laws which are free from any fault and falsification because
they are sent down from the side of allah (s.w.t.) and by an infallible
figure, i.e. a godly prophet.

" ... and none were at odds over it, except those very (people)
whom it was given unto, ... "

3- the best way of solution to contradictions is faith in the
resurrection. this doctrine utilizes the subject of glad tidings to prevent
the appearance of contradictions, and uses the subject of warning as its
remedy.

4- the worst kind of contradiction is the intentional one which
comes forth with the aim of jealousy and oppression while there are
clear evidences available.

" ... after clear arguments had come to them, revolting among themselves. ..."

5- the path to the solution of contradiction, therefore, is belief in
truth and obeying the law of prophets:

" ... so allah guided by his will, those who believed ... "

6- the critical statement of the qur'an is targeted to that
pertinacious contradiction in which a person does not accept the
judgement of prophets appointed by allah based on the divine law,
else the contradictions and disputes that finally surrender to justice are
not objected. this kind of diversity is similar to the two pans or scales
of a balance which move up and down until one finally parallels with the
other.

" ... regarding that which people had differed about the truth. ..."

7- there sometimes appear disputes between the believers, too,
but they will be led under the guardianship of allah; while disbelievers
will be wandering in darkness forever.

" ... and allah guides whomever he wills to the straight path. "

8- rescue from contradiction is, surely, counted "the straight
path. "