the question 'la madh'habiyyah vs. barelwis (meaning ahl al-sunnah, aka sufis in the arab world).' who forms the bigger threat to shariah?" is a loaded question.
it assumes that barelwis are a threat to shariah, and la madh'habiyyah as well. the question asks which is bigger.
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barelwis AKA sunnis or sufis, i.e. ahl al-sunnah are the followers and upholders of shariah, as done by our elders for the past 1400+ years. after the 5th century, almost every major imam followed a madh'hab. even those claimed to be mujtahid muTlaq such as ibn taymiyyah belonged to a madh'hab. ibn taymiyyah in his works mentions 'the four madh'habs' often.
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as for la madh'habiyyah, they are biggest threat to islam because they encourage free thinking without any knowledge or reflection. which is worse than atheist and mulHid freethinking.
free-thinking, admired in the west, and which is fashionable nowadays isn't entirely free. they expect it to be within the bounds of their frames of references with regards to their own definitions of humanity, justice, fairness and what they deem to be independent of authority and purely according to what they admit as reason.
a freethinker will not admit the opinion of an illiterate in issues related to knowledge, and particularly in issues that require domain knowledge. for example, which court would admit an illiterate or even a college dropout to represent someone in court? representing oneself is also not without danger:
https://www.theguardian.com/commentisfree/2009/feb/10/law-court-representation-barristers
as the lawyer in the above article says:
Unless you find yourself in the Arctic wilds with an enlarged appendix, or trapped beneath a boulder in a national park, you wouldn't operate on yourself with a Swiss pocket knife, however well you whittle a stick or hold your cutlery. Why would you then stand up in a court of law, however eloquent you are, or disarmingly amusing in dinner-table conversation, and conduct your own representation in a trial of real importance?
something we have been saying for ages. one cannot turn up with a bunch of law books - well, even a graduate with a degree in law cannot represent someone until they obtain a license. check this opinion:
and here from the law dictionary:
the relevant passage that every moron who calls himself a laa-madh'habi should read and shudder is highlighted below:
Unfortunately, there are no circumstances under which you'll be able to represent your accused acquaintance without first passing the bar exam in your state. In fact, individuals who have not been admitted to a state bar are explicitly banned from practicing law within that jurisdiction. This prohibition extends to laypeople as well as bar-certified lawyers from other areas. Despite his or her obvious legal experience, there is no guarantee that a seasoned lawyer who has been cleared to practice law in Oregon will be permitted to represent a client who stands trial in Texas. Although many states have "reciprocal" arrangements that permit lawyers with "outside experience" to practice law within their borders, this occurs on a case-by-case basis. Further, non-lawyers are not permitted to take advantage of such arrangements.
In fact, practicing law without a bar license is a crime. If you attempt to represent an acquaintance without a license, you'll probably find yourself in one of two unpleasant situations.
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what about medicine? check:
http://www.criminaldefenselawyer.com/resources/practicing-medicine-without-a-license.htm
this wikipedia article is a good start to identify professions that require licenses:
https://en.wikipedia.org/wiki/Practicing_without_a_license
Fields where practicing without a license may carry civil or criminal penalties include
lawyer,
physician,
physician assistant,
surgeon,
coroner,
medical examiner,
paramedic,
funeral director,
osteopath,
chiropractor,
dentist,
pharmacist,
engineer,
pilot,
broadcasting,
nurse,
veterinarian,
midwife,
teacher,
psychologist,
surveyor,
detective,
social worker,
architect,
barber,
hairdresser,
electrologist,
tattooist,
cosmetologist,
real estate agent,
plumber,
florist,
accountant, and
masseuse.
would you hire a person with no previous plumbing experience to fix your toilet? would you allow a technician without basic knowledge of receivables/payables and debit/credit to manage the accounts of a company? would you ask a delivery boy, who has experience in only riding motorcylcles to drive the bus or run your trains? would you ask a chartered accountant without a pilots license to fly the commercial airliner, even if he has thousands of hours clocked on a flight simulator?
but hey, no!
for the qur'an and hadith - it is open. anyone can interpret it. attend a nouman ali khan course for a few months and become capable of doing tafsir! even if prominent mufassirin spent a lifetime mastering two dozen subjects before penning a translation or tafsir. but morphology and grammar is sufficient for a translation and tafsir. laa Hawla wa la quwwata illa billah.
a taxi driver who cannot speak his mother tongue properly, or a tea-vendor incapable of pronouncing words in his mother tongue, can become an expert in the qur'an and deriving aHkam from qur'an and hadith, without any previous training. a teacher who spent the better part of his life in worldly activities and after retirement found religion (as he has nothing better to do) suddenly becomes an expert in doling out ahkam and commenting on opinions of experts.
abu hanifa* was a man, and i am a man. he had an opinion and so do i.
*raHimahullah
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essentially la-madh'habi is the islamic equivalent of practising law without a license.
it is a crime.
Allah ta'ala knows best.