Mankind were but one community, then they differed (later); and had not it been for a Word that went forth before from your Lord, it would have been settled between them regarding what they differed.Allah then tells us that Shirk was new among mankind. It was not in existence in the beginning. He tells us that people were believers in one religion and that religion was Islam.Ibn Abbas said:"There were ten centuries between Adam and Nuh. They were all on Islam. Then differences among people took place. They worshipped idols and rivals. So Allah sent extensive evidence and irrefutable proof with His Messengers."لِّيَهْلِكَ مَنْ هَلَكَ عَن بَيِّنَةٍ وَيَحْيَى مَنْ حَىَّ عَن بَيِّنَةٍSo that those who were to be destroyed (for rejecting the faith) might be destroyed after a clear evidence, and those who were to live might live after a clear evidence. (8:42)Allah's statement:وَلَوْلَا كَلِمَةٌ سَبَقَتْ مِن رَّبِّكَAnd had not it been for a Word that went forth before from your Lord...means that if Allah had not decreed He would not punish anyone until the evidence is established against them. And also that if He had not given creatures a respite until a defined term had passed, He would have judged among them in what they disputed. Then He would have caused the believers to be happy and delighted and the disbelievers to be miserable and wretched