﴿ وَيَوْمَ نَبْعَثُ فِى كُلِّ أُمَّةٍۢ شَهِيدًا عَلَيْهِم مِّنْ أَنفُسِهِمْ ۖ وَجِئْنَا بِكَ شَهِيدًا عَلَىٰ هَٰٓؤُلَآءِ ۚ وَنَزَّلْنَا عَلَيْكَ ٱلْكِتَٰبَ تِبْيَٰنًۭا لِّكُلِّ شَىْءٍۢ وَهُدًۭى وَرَحْمَةًۭ وَبُشْرَىٰ لِلْمُسْلِمِينَ ﴾

“for one Day We shall raise up within every community a witness against them from among themselves. And thee [too, O Prophet,] have We brought forth to bear witness regarding those [whom thy message may have reached], inasmuch as We have bestowed from on high upon thee, step by step, this divine writ, to make everything clear, and to provide guidance and grace and a glad tiding unto all who have surrendered themselves to God.”

It is the way of Almighty God that He entrusts the task of delivering warnings and of giving good news to a community through an individual selected from that very community. This is why the prophets who came to various communities were members of those communities. Now the Muslim community is required to fulfill the responsibilities of calling for the Truth and of testifying in every community till the Day of Judgement. The preachers of the various communities of this world will in the Hereafter be God’s witnesses or testifiers of those communities. It will be on the basis of their testimony that decisions will be made regarding the reward or punishment to be given to all individuals of the community. There are descriptions in the Quran of all matters of major moral and practical importance. Indeed, every revealed book which has come to mankind on behalf of God has contained such descriptions. However, the main focus is not on worldly knowledge, but on success or failure in the Hereafter. This is true of the Quran, which lays down broad principles covering the entire range of conduct which will lead to success in the Hereafter. (Neglect of these principles will lead to failure.) Those who are guided by them will merit divine blessings, while those who neglect them will only give grounds for their own destruction.