Sunan an-Nasa'i 6
سنن النسائي#6Sahihأَخْبَرَنَا حُمَيْدُ بْنُ مَسْعَدَةَ، وَعِمْرَانُ بْنُ مُوسَى، قَالاَ حَدَّثَنَا عَبْدُ الْوَارِثِ، قَالَ حَدَّثَنَا شُعَيْبُ بْنُ الْحَبْحَابِ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " قَدْ أَكْثَرْتُ عَلَيْكُمْ فِي السِّوَاكِ " .
It was narrated that Anas bin Malik said:"The Messenger of Allah (ﷺ) said: 'I have indeed urged you with regard to the Siwak
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih Bukhari
In-book reference: 1:6