Controversial aḥādīth in terms of arrangement in Nasāi's Sunan and their comparison with Muslim's Sahīh

'Ilal al-ḥadīth (hidden defects in hadith) which is one of the most important branches of ḥadith sciences, plays a crucial role in differentiating the strong aḥādīth from the weak ones. This is because the detection of problematic hidden defects in aḥādīth which are not possible to notice at the first sight, could be followed out by a small number of scholars. al-Nasā'ī who is prominent in his knowledge of al-'ilal as well as his munakkid (critic) position, is among those few scholars who were able to detect the hidden defects of aḥādīth. The headings of his work Sunan, which comes in form of "اختلاف على..." (ikhtilāf 'ala) are among the places in which he set forth his knowledge in al-'ilal. In these headings he collected the chains of aḥādīth, presented the differences between them and tried to reveal the defects which were not noticed at first sight. Thus, he exhibited a practical method of detecting al-'ilal and presented it in a general arrangement frame. This work has focused intensively on al-Nasā'ī's arrangement method for the aḥādīth which are narrated in these headings. To make it understandable, this arrangement method is compared with Muslim's Sahīh which has a similar method with al-Nasā'ī in reporting the aḥādīth. As a result of the research, it has been concluded that the practical dimension of detecting al-'ilal in the aḥādīth is set forth in the majority of the headings which put the controversy in the center. Moreover, it is seen that the aḥādīth were not reported in a uniform order in the mentioned headings and that the authentic aḥādīth were reported before the aḥādīth with 'ilal or vice versa. In the headings of the sub-chapters which we dealed by the way of sampling, it is identified that al-Nasā'ī reported authentic aḥādīth before the weak ones with a very slight difference. In other words it is seen that the percentage of the samples in which the weak ahadith are reported before the authentic ones is very close to the first situation.