Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
quran:3:78

And indeed, there is among them a party who alter the Scripture with their tongues so you may think it is from the Scripture, but it is not from the Scripture. And they say, "This is from Allah," but it is not from Allah. And they speak untruth about Allah while they know.  

And there is a group, a party, of them, the People of the Scripture, like Ka‘b b. al-Ashraf, who twist their tongues with the Book, altering it by reciting it not according to the way in which it was revealed, but according to the way in which they have distorted it, as in the case of the descriptions of the Prophet (s) and other similar matters; so that you may suppose it, such distortion, as part of the Book, that God revealed; yet it is not part of the Book; and they say, ‘It is from God’, yet it is not from God, and they speak falsehood against God, while they know, that they are liars.
القرآن:٣:٧٨

وَإِنَّ مِنْهُمْ لَفَرِيقًا يَلْوُونَ أَلْسِنَتَهُمْ بِالْكِتَابِ لِتَحْسَبُوهُ مِنَ الْكِتَابِ وَمَا هُوَ مِنَ الْكِتَابِ وَيَقُولُونَ هُوَ مِنْ عِنْدِ اللَّهِ وَمَا هُوَ مِنْ عِنْدِ اللَّهِ وَيَقُولُونَ عَلَى اللَّهِ الْكَذِبَ وَهُمْ يَعْلَمُونَ  

{وإنَّ منهم} أي أهل الكتاب {لفريقا} طائفة ككعب بن الأشرف {يلوون ألسنتهم بالكتاب} أي يعطفونها بقراءته عن المنزل إلى ما حرفوه من نعت النبي ﷺ ونحو {لتحسبوه} أي المحرف {من الكتاب} الذي أنزله الله {وما هو من الكتاب ويقولون هو من عند الله وما هو من عند الله ويقولون على الله الكذب وهم يعلمون} أنهم كاذبون.