Sunan an-Nasa'i 4129
سنن النسائي#4129Sahihأَخْبَرَنِي إِبْرَاهِيمُ بْنُ يَعْقُوبَ، قَالَ حَدَّثَنَا يَعْلَى، قَالَ حَدَّثَنَا الأَعْمَشُ، عَنْ أَبِي الضُّحَى، عَنْ مَسْرُوقٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ تَرْجِعُوا بَعْدِي كُفَّارًا " . مُرْسَلٌ .
It was narrated from Masruq that:The Messenger of Allah [SAW] said: "Do not revert to disbelievers after I am gone." It is Mursal
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 ZaiHasan
In-book reference: 37:164