Abrogation

Rhology provides an example to illustrate how difficult it can be to exegete the Quran.

The Islamic concept of abrogation (naskh) doubtless factors into the equation as well:

Those Westerners who manage to pick up a translation of the Quran are often left bewildered as to its meaning thanks to ignorance of a critically important principle of Quranic interpretation known as "abrogation." The principle of abrogation -- al-naskh wa al-mansukh (the abrogating and the abrogated) -- directs that verses revealed later in Muhammad's career "abrogate" -- i.e., cancel and replace -- earlier ones whose instructions they may contradict. Thus, passages revealed later in Muhammad's career, in Medina, overrule passages revealed earlier, in Mecca. The Quran itself lays out the principle of abrogation:

2:106. Whatever a Verse (revelation) do We {Allah} abrogate or cause to be forgotten, We bring a better one or similar to it. Know you not that Allah is able to do all things?

It seems that 2:106 was revealed in response to skepticism directed at Muhammad that Allah's revelations were not entirely consistent over time. Muhammad's rebuttal was that "Allah is able to do all things" -- even change his mind. To confuse matters further, though the Quran was revealed to Muhammad sequentially over some twenty years' time, it was not compiled in chronological order. When the Quran was finally collated into book form under Caliph Uthman, the suras were ordered from longest to shortest with no connection whatever to the order in which they were revealed or to their thematic content. In order to find out what the Quran says on a given topic, it is necessary to examine the other Islamic sources that give clues as to when in Muhammad's lifetime the revelations occurred. Upon such examination, one discovers that the Meccan suras, revealed at a time when the Muslims were vulnerable, are generally benign; the later Medinan suras, revealed after Muhammad had made himself the head of an army, are bellicose.