The question about how the door of Ijtihad was closed needs some background about the definition of Ijtihad, its history and the background on the development of the schools of Fiqh. Only after this we can talk about the closing of the door of Ijtihad.
Ijtihad is the process by which a person can go to the text (Qur'an and the Sunnah), study and understand it and derive a Hukm (rule) from it regarding a specific issue at hand. There are some pre-requisites for Ijtihad: for example, knowing the Arabic language, its grammar, definition, history, etc.; regarding the issue at hand, a Mujtahid has to know all or most of the Hadith and the Qur'anic Ayat regarding the issue, etc. There are also other requirements for a person to be a Mujtahid.
There is no clergy in Islam, thus Ijtihad is open to anyone who is qualified for it. No one can monopolize on understanding Islam. In other words, there is no official spokesman for Islam. In the past, Muslims practised Ijtihad in very effective and creative ways. There was a time in which Ijtihad was the general rule and the exception was the Taqleed (following rules by a person who did Ijtihad). During that era, Muslims were attached to the text, (Qur'an and the Sunnah) not to the scholars. And even the scholars used to teach the people that they should abandon his (scholar's) own opinion if they found an evidence (from the Qur'an and the Sunnah) stronger than his.
However, after that era, Muslims started to decline and the curve started to go down. This happened due to many factors: One of these factors is the neglecting of Arabic language. Muslims also started to think that the previous scholars offered us whatever is needed. Thus, there is no need for Ijtihad. All that is needed, according to this wrong understanding, is a person well educated about a specific Madhab and trying to study the old books of Fiqh. Now, the people started to get attached to the Madhab and not to the text.
In the fourth century of Hijrah a person called al-Qaffal issued a Fatwa closing the door of Ijtihad, thus he was called al-Qaffal which means the one who closes something. Although Ijtihad was declared to be closed, but, practically, Muslims continued Ijtihad and it was not abandoned completely. From time to time one would hear of a Mujtahid, such as as-Shawkanee and others.
The present situation, however, is even more dangerous, because there are people who are trying to address the issue in a wrong way. They are trying to say that Ijtihad must be opened without any restrictions. Meaning, that anyone, even an unqualified individual, may practise Ijtihad. Or they try to get rid of the rules of Usul ul Fiqh in order to make Ijtihad more easy. But in reality, this is not Ijtihad.
Ijtihad has to be defined and cannot be loose. The doors of Ijtihad should be kept open, but, they should not be broken.
Excesses are forbidden in our religion and we are commanded to be moderate in all our activities in life. Even in matters of religion we are warned against committing any excesses, as is clear from the following Qur'anic verses : "O people of the book, commit no excesses". (4:171)
"Say O people of the Book, exceed not in your religion". (5:80)
On spending, the Holy Qur'an says "Make not thy hand tied (like a niggard's) to your neck, nor stretch it forth to its utmost reach, so that thou become blameworthy and destitute." (17:29)
"Those who when they spend, are not extravagant and not niggardly, hold a just (balance) between those (extremes) (25:67)
As regards the good things and the lawful, the Qur'an says: "O ye who believe, make not unlawful the good things which God hath made lawful for you, but commit no excess for God loveth not those given to excess." (5:90)
On speaking aloud the Qur'an says "Neither speak thy prayer aloud, nor speak it in a low tone, but seek a middle course between." (17:110)
Even on fighting those oppressors who fight you, the Qur'an says: "Fight in the cause of God, those who fight you, but do not transgress limits; for God loveth not transgressors". (2:190)
The Ummah of Islam is justly balanced, and there is no extremity in matters. The true path is the even path, the path of rectitude. The Holy Qur'an says: "Thus have we made of you an Ummah justly balanced, that ye may be witnesses over the nations." (2:143)
Islam calls for establishment of peace on earth and condemned violence, aggression and oppression. Islam preaches brother hood, tolerance and communal harmony.
Masturbation in Islam is Haram. Its harms are great and it has disastrous consequences as established by doctors who have attested to its gravity and detriment. Allah Ta'ala says in the Noble Qur'an concerning the qualities of the people of Iman: 'And those who guard their modesty - save from their wives or the (slaves) that their right hands possess, they are not blameworthy. But whosoever craves beyond that, such are transgressors.' (Mu'minoon 5-7)
It is apparent that this act is contrary to that with which Allah Ta'ala has described the people of Iman - and it entails transgression and injustice upon one's self. Therefore, it is incumbent to abstain from it and take recourse to what Prophet (Pbuh) has prescribed for bachelors wherein he said, 'O members of the youth, those of you who have the means to get married then surely do so, because therein lies the greater protection of ones eyes and private parts. And as for those who do not have the means, then let them hold onto fasting because it weakens and breaks the passion (and desire within a person).'
It is hoped, Insha Allah, that by means of this Nabawi (prophetic) prescription you will finally be able to discard and leave this abominable and wicked act. However, there is no harm in referring to a doctor as well as seeking guidance on this matter for those who are not able to fast and for those who are not able to subdue their passions by fasting as Prophet (Pbuh) said, 'Allah Ta'ala has not sent down any sickness but together with it he sent down a cure as well. Those who have knowledge will be cognisant of it and the ignorant will remain ignorant of it.'
The Prophet (Pbuh) said, 'O servants of Allah! Treat one another with medication. However, do not resort to unlawful means.'
It has been proven medically that masturbation causes numerous illnesses. From among them are:
1.. It weakens the eyesight and decreases its sharpness to a great extent.
2.. It causes the private part to become frail and feeble and it creates a partial or total laxity in it, resulting in the person becoming more resembling to women, due to the loss of his distinctive manliness by means of which Allah Ta'ala has granted man virtue over woman. He is thus unable to get married. And in the event of him getting married, he will not be able to fulfil the responsibilities of marriage as required. This will cause his wife to cast her gaze on other men, resulting in such harms which are apparent.
3.. It creates a weakness in the nerves and sinews due to the physical exertion involved in this act.
4.. It disrupts and upsets the digestive system, thus impending this process.
5.. It creates an impediment in the growth of the body organs, the penis and testicles in particular, thus they do not grow to their natural limit.
6.. It causes an inflammation in the testicles resulting in premature ejaculation to this extent that by mere frictional contact of the penis, ejaculation occurs.
7.. It causes pain in the vertebral column (spine) - the place from which sperm originates - due to which crookedness and bending occurs in the back.
8.. Due to constant ejaculation, the sperm no more remains thick and dense as it normally occurs in males. This results in a deficiency in sperm and in many cases leaving it faint and thin which is not 'mighty enough' to impregnate. This is the cause for such children to be more prone to disease and illness as against those who are born from natural sperm.
9.. It causes trembling and instability in some parts of the body like the feet.
10.. It weakens the cerebral glands, thus weakening the faculty of perception. It also decreases one's intellect and can even lead to mental disorders and insanity.
11.. Finally, we beseech of the Almighty Allah Ta'ala for protection from all evils, for us and all Muslims.
(Abdul Aziz bin Abdullah bin Baaz, Grand Mufti and Head - Department of Islamic Research, Iftaa and Propagation - Saudia Arabia
Extracted from: 'Whither O Youth' Sheikh Muhammad bin Saleh al-Uthaymin published by Madrassa Arabia Islamia - Azaadville)