The task of the Holy Quran was to reform people of all eras. The objective of the Quran was to transform mankind from an animal state to a human state, and thence to make of humans civilised individuals by inculcating good manners, so that a transformation could be brought about by acting within the dictates of the shariah and its injunctions; and finally, so that they could be made into godly people. These words are brief, but they encompass thousands of facets. Since the Jews, naturalists, fire-worshippers and other nations were engrossed in evil practices, it is for this reason that upon the instruction of Allah, the Holy Prophet, peace and blessings of Allah be upon him, addressed all the people, saying:
قُلۡ یٰۤاَیُّھَا النَّاسُ اِنِّیۡ رَسُوۡلُ اللّٰہِ اِلَیۡکُمۡ جَمِیۡعًا
Say, ‘O mankind! Truly I am a Messenger to you all.’
And so it was necessary for the Holy Quran to gather within itself all those teachings that had been instituted at various points in time and to possess all the truths that were conveyed from heaven to the people of the world in various times through numerous Prophets. The Holy Quran had the whole of humanity in view, not a specific people, country or era. The Gospel, on the other hand, had a specific people in view and this is why the Messiah, on whom be peace, repeatedly said: ‘I have come in search of the lost tribes of Israel.’
(Hazrat Mirza Ghulam Ahmadas, Malfuzat, Vol. 1, p. 83)