«فالزيادة عليه بخبر الواحد والقياس لا تجوز»
An addition by a solitary report or analogy may not alter that established ruling.
This is a distinctive Hanafi principle concerning an unrestricted Qur’anic rule that can already be applied. Making an additional condition indispensable to validity can sometimes count as changing that rule.
This does not dismiss solitary reports. They may establish an obligation, Sunnah, commendable practice, or complementary ruling without changing the original Quranic requirement. Other legal-theory schools analyze the relationship differently.