The following verse is interpreted by some as allowing people of other faiths to adhere to their faiths because these can lead to God as well:
To each among you had We prescribed a Law and a Way. If Allah had so willed, He would have made you a single people, but [His plan is] to test you in what He has given you; so try to outdo one another in virtues. The return of you all is to Allah; it is He that will show you the truth of the matters in which you dispute. (5:48)
On the basis of this verse, many non-Muslims ask the reason for following the Qur’ān and Islam because as the verse says they can simply follow their own faiths and achieve salvation?
I am afraid that this inference is not correct because the said verse has been interpreted while disregarding the context. To understand what it says, first let us look at it in relation to the preceding and succeeding verses. They read:
It was We who revealed the Torah to Moses; therein was guidance and light. In accordance with it the obedient Prophets of Allah, Rabi scholars and the jursits of the Jews used to decide the affairs of the Jews because they had been entrusted with the book of Allah and made witnesses ....And in their footsteps We sent Jesus the son of Mary in testification of the Book before him; therein was guidance and light and We gave him Injil as a guidance and admonition to those who fear Allah and it is incumbent upon the recipients of Injil to decide [according to the directives] contained in it...And to you [O Prophet] We sent the scripture in truth according to the confirmation of the scripture that came before it, and as a guardian. So judge Between them by what Allah has revealed, And follow not their vain desires, diverging from the truth that has come to you. To each among you had We prescribed a Law and a Way. If Allah had so willed, He would have made you a single People, but [His plan is] to test you in what He has given you; so try to outdo one another in virtues. The return of you all is to Allah; it is He that will show you the truth of the matters in which you dispute. And this [He commands]: Judge between them by what Allah has revealed, And follow not their vain desires, but beware of them lest they beguile you from any of that [teaching] which Allah has sent down to you. And if they turn away, be assured that for some of their crimes it is Allah’s purpose to punish them. And truly most men are rebellious. Do they then seek after a judgement of [the days of] Ignorance? But who, for a people whose faith is assured, can give better judgement than Allah? (5:44-50)
A simple reading of these verses tells us:
1. This cluster of verses is narrating Allah’s scheme of the history of Wahī (divine revelation) to three major Prophets who received this guidance in the form of Books.
2. Each of the three Prophets were given a Book so that he could decide the affairs of his people through his Book.
3. Since the first two Books could not be preserved in their original form, the final Book: the Qur’ān was revealed as a guardian and judge between the older books.
4. The Law and the Way (ie the Sharī‘ah) were different to all these nations (whilst the basics in faith were the same). The reason being that a change in this law should become a source of trial and test for the subsequent nation. The test was that they willingly accept this change or not since the basics were the same; only the outward appearance in law changed. An example of this is that the teaching of Tawhīd (monotheism) never changed in any divine Book but the nature and quantity of worship rituals (which were the Law), for example, changed.
5. Allah could have kept all the people on His path by force but He did not do so. He did not want people to follow His path due to some coercion. He wanted people to decide freely for themselves. So He gave them the choice to choose.
6. The Prophet Muhammad (sws) was directed to judge between the previous nations according to the Qur’ān since this was the final and authentic version of the Words of Allah.
7. If the people of the previous nations do not listen to him and deliberately deny his message, then they will face a grievous doom very soon.
If this contextual analysis is correct, the inference to which you have referred, I should believe, does not arise.