Almost all jurists agree that refusal to accept an ijma' other than an ijma of suhaba or an ijma established with continuity, tawatur, in all the previous generations of Muslims (ijma' qat'i), like the Qur'anic verses, is not kufr. In case of ijma' suhaba and ijma' qat'i two cases are distinguished:
Ijma' on matters related to the fundamentals of din whose comprehension is needed by all Muslims, e.g. the belief in the oneness of God and in prophethood, the obligatory character of the five "pillars" of Islam, facing the Ka'bah while praying, the number of rak'at in each prayer, the times for hajj and fasting, prohibition of adultery, alcoholic drinks, stealing and usury.
Ijma' on matters whose knowledge is expected only from "specialists" (khawas), e.g. marrying at the same time a woman and her paternal aunt or a murderer being cut off from inheritance.
There seems to be a general agreement that refusal to accept ijma' suhaba or ijma qat'i on matters of the first category is kufr but opinions differ as to whether a refusal to accept ijma' suhaba or ijma qat'i on matters of the second category is also kufr.(31)
Imam al-Harmayn (Diya al-Din 'Abd al-Malik al-Juwayni) says that refusing to accept a method of deriving rules of shari'ah is not kufr. Therefore, a person does not accept the principle of ijma' as a valid source of rules is not a kafir. Only a person who accepts the principle of ijma' and also recognizes that a certain ruling is based on ijma' and then refuses to accept it can be declared as committing kufr.(32)