Many Muslims adopt the teachings of a particular mazhab. There are historical and geographical reasons for this. Generally each mazhab follows his interpretation on certain elements of fard, such as the halal and haram, and aspects of salat.
The mazhabs did not differ on the fundamental pillars of our faith, such as tauhid.
All mazhabs are learned scholars of the highest order. We generally follow their interpretation because as laymen, we do not have enough knowledge to understand and interpret religious issues correctly.
All the main mazhabs respected each other’s opinions. And, if we are trained properly in Quran and Sunnah, we can make our own conclusions on what each mazhab says. After all Islam tells us to seek knowledge but many of us don’t heed this call. But, not being scholars ourselves, we are allowed, and even encouraged, to rely on a mazhab to guide us on the correct interpretation of a particular matter by the Quran and Sunnah. If we have solid grounds, we can have a different interpretation or refer to the conclusions of another mazhab for the same issue.
None of the mazhabs claimed that only his way is correct. Only prophets and messengers can make that claim. Further, the concept of the mazhab jurisprudence came after the time of Rasulullah SAW. It is not part of the Quran and Sunnah, it is part of interpreting the Quran and Sunnah. There is a big difference.
It is WRONG is when one Muslim claims that only his mazhab is correct and all others are wrong. To start name calling and labelling the followers of other mazhab. To imply that their Islam is wrong and only the followers of his mazhab follow the Quran and Sunnah.
Most of the people who do this don’t even know what their own mazhab says about an issue. For example someone may claim to be a Shafie but has no idea what Imam Shafie's full name was, what nationality he was, where he studied Islam, and has not even read a single book he wrote! This person is just repeating hearsay from society, and claims the Shafie way is right and all others are wrong, only because he happened to be brought up in Malaysia and not Pakistan. It’s not based on research, facts or data. It's not based on any flaws in the creed of the other mazhab. It's not based on any of Imam Shafie’s teachings even. It’s based purely on arrogance, prejudice and self righteousness.
This is ignorance of the highest order. Usually spread by those who have very little Islamic knowledge or manner, but think they are scholars. Sometimes spread by those who don’t even fulfil their fard obligations, but think they are more devout than others. The twin of ignorance is arrogance. One can’t have one trait without the other. And no one with an atom’s weight of arrogance will enter jannah.
Brothers and sisters, step away from this. We are followers of the Quran and Sunnah first and foremost. We turn to our mazhab and imams for guidance and the fine tuning of the rules. It is not worth fighting about or creating division over small issues such as whether one’s index finger should be still or rotate when reciting the Tahiyyat, while we ignore real problems such as the situation in Syria and Al Quds.
As Muslims, it is sheer arrogance to look down on other fellow Muslims, what more entire sectors of them just because you think your mazhab is superior. Remember that a sin may cause you to enter jannah if it causes you to repent, but your good deeds may lead you to jahannam if it causes you to be arrogant.
Get over it, and get over yourself. Islam is one.