Quran, in certain places, supersedes other parts." Abu al-'Ala' ibn al-Shikhkhir (d. 107/725), a Tabi'i, (i.e. one of the generation of Muslims who followed the Sahaba -- the companions of Muhammad) is reported to have said much the same thing according to a Sahih Muslim hadith. History In "general terms", the idea of a divine process whereby the decisions of a monotheist God can be superseded by His later decisions precedes "even the foundation of Islam itself," (according to John Burton), being found in Epistle to the Hebrews 8:13; 10:9 of the New Testament. While Muhammad is reported to have abrogated parts of the sunnah by "explicit abrogation" (see below), there are no reports of him talking about abrogated verses in the Quran or explaining any theory of abrogation. Thus the classical theory of naskh "cannot go back to the Prophet". This is an argument against the theory according to its opponents — "it is inconceivable that the Prophet had left such an important problem to the discretion of the people ..." Reports of companions emphasizing its importance There are, however, introductory stories in almost all classical naskh works about how (younger) companions of Muhammad — some of his "oldest and most determined supporters" revered by pious Muslims — emphasized the importance of belief in and knowledge of the theory of naskh. Many recount an incident where a Kufan preacher is banned from expounding the Quran on account of his ignorance of the principles of naskh by an early 'ilmic authority figure (usually Rashidun Caliph 'Alī, but sometimes also Ibn 'Abbās, cousin of Muhammad and hadith narrator). In one report Ali told a judge who had no knowledge of nasikh that he was "deluded and misleading others", in another he evicted a preacher from a mosque for being ignorant of the science of abrogation. Umar is reported to have told Muslims that despite the fact that Ubay ibn Ka'b was "the best Quranic expert among us ... we ignore some of what" he says because he disregarded abrogation and told others he refused to "abandon anything I heard from the Messenger of Allah". Another set of Hadith emphasize how those who speak publicly on fiqh (Islamic law) without expert knowledge in naskh not only endanger their own immortal souls but also the souls of those who listening to them. Some (John Burton) have questioned the authenticity of these hadith, finding