Since Prophet Adam (alaihi-salam), they changed and denied the religions revealed in every century by saying that they were the words of ignorant primitive people. Such assertions made by disbelievers are quoted, and answered in many parts of the Quran al-Karim. For example, Allahu Taala says...

It is impossible to escape torment in the Hereafter for those who deviate as much as a hair’s breadth from the creed and iman communicated by the Ahl as-Sunna scholars, the great and pious people. It is understood by the human mind, the Quran alKarim, all hadith sharifs and the great religious...

The first thing necessary for all people is to have iman and the creed of the Ahl as-Sunna scholars as communicated in their books. It is these scholars who have explained the way of our Prophet Muhammad (alaihi-salam), who have comprehended murad-i ilahi (the divine purpose) of the Quran...