What are the sources of Islamiclegislation?.

Praise be to Allaah.
The sources of Islam on which all
beliefs, principles and rulings are
based are represented by the
two Revelations: the Qur ’aan and
Sunnah. This is what is implied
by Islam being a divinely-
revealed religion: its pillars are
based on infallible texts that
were sent down from heaven,
which are represented in the
verses of the Holy Qur’aan and
the texts of the saheeh Prophetic
Sunnah.
Imam al-Shaafa’i (may Allaah
have mercy on him) said:
No view is binding unless it is
based on the Book of Allaah or
the Sunnah of His Messenger
(peace and blessings of Allaah be
upon him). Everything other than
them should be based on them.
End quote.
Jimaa’ al-‘Ilm.
From these two sources the
scholars derived other principles
on which rulings may be based.
Some scholars called them the
sources of sharee ’ah or the
sources of Islamic legislation.
They are: ijmaa ’ (scholarly
consensus) and qiyaas (analogy).
Imam al-Shaafa’i (may Allaah
have mercy on him) said: No one
has any right whatsoever to say
that something is halaal or
haraam except on the basis of
knowledge, and the basis of
knowledge is a text in the
Qur’aan or Sunnah, or
ijmaa’ (scholarly consensus) or
qiyaas (analogy). End quote.
Al-Risaalah (39).
Ibn Taymiyah (may Allaah have
mercy on him) said:
If we say Qur’aan, Sunnah and
ijmaa’, they all stem from the
same source, because the
Messenger agrees with
everything that is in the Qur’aan,
and the ummah is unanimously
agreed upon it in general. There
is no one among the believers
who does not believe it is
obligatory to follow the Book.
And everything that the Prophet
enjoined in his Sunnah, the
Qur ’aan obliged us to follow it.
So the believers are unanimously
agreed upon that, and everything
on which the Muslims are
unanimously agreed can only be
true and in accordance with what
is in the Qur ’aan and Sunnah. End
quote.
Majmoo’ al-Fataawa (7/40).
Dr. ‘Abd al-Kareem Zaydaan said:
What is meant by the sources of
fiqh is the evidence from which it
is derived and on which it is
based. If you wish, you may say:
The sources from which it is
derived. Some people call these
sources the “sources of
sharee’ah” or “the sources of
Islamic legislation.” No matter
what they are called, the sources
of fiqh all derive from the
Revelation (wahy) of Allaah,
whether it is Qur ’aan or Sunnah.
Hence we prefer to divide these
sources into original sources,
namely the Qur ’aan and Sunnah,
and secondary sources to which
the texts of the Qur ’aan and
Sunnah refer, such as
ijmaa ’ (scholarly consensus) and
qiyaas (analogy). End quote.
Al-Madkhil li Diraasat al-
Sharee ’ah al-Islamiyyah (p. 153).
With regard to sources other
than these four, such as the
opinions of the Sahaabah,
istihsaan (discretion), sadd al-
dharaa ’i’ (blocking the means
that lead to evil), istishaab, ‘urf
(custom), the laws of those who
came before us, al-masaalih al-
mursalah (things that serve the
general interests of the Muslims)
and so on, the scholars differed
as to how valid it is to use them
as evidence. According to the
view that they are acceptable –
all or some of them – they are
secondary to the Qur’aan and
Sunnah and should be in
accordance with them.
And Allah knows best.