There is no explicit Quranic or Prophetic command requiring a Muslim to formally commit to one of the four Sunni madhhabs exclusively. The obligation is to follow the Quran and Sunnah; the madhhabs are simply organized methodologies scholars developed to derive rulings systematically and consistently. For a scholar with the training to examine primary evidence directly (ijtihad), moving between positions based on the strength of proof is considered legitimate, and the Prophet's teaching that a sincere, qualified judge is rewarded whether his conclusion is right or wrong reflects this tolerance for reasoned differences. For the average layperson without such training, however, the majority of scholars recommend following a single recognized school consistently, both out of practical necessity, since few people can independently evaluate legal evidence, and to avoid talfiq, the practice of selectively picking the easiest ruling from different schools on unrelated matters to suit personal convenience, which most scholars discourage as compromising the discipline and coherence each madhhab was built to preserve.
Q&A · Sects & Comparative Belief
Is it necessary for a Muslim to follow one specific madhhab?
References
Sahih al-Bukhari 735216:43
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.