The Authority of Revelation

وَلَقَدْ ءَاتَيْنَا مُوسَى ٱلْكِتَـٰبَ وَجَعَلْنَا مَعَهُۥٓ أَخَاهُ هَـٰرُونَ وَزِيرًا

And We had certainly given Moses the Scripture and appointed with him his brother Aaron as an assistant.