وَمَا أَرْسَلْنَا مِنْ قَبْلِكَ مِنْ رَسُولٍ إِلَّا نُوحِي إِلَيْهِ أَنَّهُ لَا إِلَٰهَ إِلَّا أَنَا فَاعْبُدُونِ
We sent no messenger before you without revealing to him that there is no deity but Me, so worship Me (Qur’an 21:25).
The verse identifies the common foundation of prophetic messages: worship belongs to God alone. Particular legal prescriptions can vary by context, but this core is not reversed.
Its argumentative force is especially clear when someone claims allegiance to earlier prophets. The claimed inheritance can be tested against the central teaching that those prophets shared.