The Prophet, who was known as'Amīn'(trustee) in the society in which he lived, for the purpose of transmitting the divine laws through generations, foretold that lying and Islam would not come side by side. In a special sense, it is stipulated that those who narrates hadiths should be free from sins, especially lying, and even have a personality in accordance with the custom in which he lived. While the narration of anyone who has a deficiency in this regard falls below the level of authenticity, the situation of those who repented later was discussed. While it was stated that the sins other than lying would be forgiven with repentance and the narrator would return to his former state, the situation of the person who lied on behalf of the Prophet was kept separate. The general opinion on the subject is that even if he repented, no hadith should be accepted from such people for eternity. The acceptance of their testimony and rejection of their narrations is due to the fact that the transmission of hadith is a matter of concern to the ummah. This is because the effect of lying in testimony is limited, whereas the harm of a person who narrates a fabricated narration is much greater. From this point of view, the hadith scholars, who say that repentance is between Allah and the servant, regard the repentance of the one who lies to the Prophet even once as doubtful. In the matter of testimony, which differs from narration in certain points, it has been stated by the scholars of fiqh that there are those whose testimony is rejected for eternity. Some scholars, on the other hand, said that narration and testimony would be accepted with repentance. However, the aforementioned issue has been theoretically analysed in the works of hadith methodology, but no separate study has been conducted considering its practical aspect. The fact that there are very few narrators who can be used as evidence on the subject, and the elaboration of the issue with the issues of narration and shahada have caused different opinions to be put forward. Therefore, in this research, the issue has been be discussed by analysing the narrators and witnesses in terms of both the claims of the scholars of the methodology and repentance. As a result, it was seen that the repentance of the narrators from their sins caused them to be cleansed due to the fact that the hadith scholars were not agreed in the reasons for al-jarh (criticism), and the issue was jurisprudential (ijtihādi). However, those who fabricated a lie in the name of the Prophet, even once, were exempted from this issue, which is the general opinion of the scholars. [ABSTRACT FROM AUTHOR]