If we were to say that no religion in the world today is correct, then this would entail believing that God is unjust because He left us to wander about on earth in sin and transgression without showing us the right way to do things, and this is impossible for a Just God. Therefore the only logical conclusion is that there is One True Religion, which contains guidance in all spheres of life, religious, moral, societal, and individual.
How do we know what this one true religion is? It is upon each and every human to investigate this matter. Humans were created to fulfill a great purpose, not just to eat, sleep and go about finding their daily sustenance and satiate their desires. In order to fulfill this purpose, one must try to find what their purpose is, and this can only be done by investigation. If one believes that there is a God, and that God must not have left humans to wander in misguidance, then they must search for the religion and way of life which God revealed. Furthermore, this religion would not be hidden or hard for humans to find or understand, for that would defeat the purpose of guidance. Also, the religion must contain the same message throughout time, since we mentioned that everything returns to one absolute truth. Also, this religion cannot contain any falsities or contradictions, for falseness or contradiction in one matter of the religion proves the falsity of the religion as a whole, since we would then doubt the integrity of its texts.
There is no other religion which fulfills the conditions mentioned above except for religion of Islam, the religion which is accordance to human nature, the religion which has been preached by all prophets since the dawn of man. Other religions found today, such as Christianity and Judaism, are the remnants of the religion brought by the prophets in their time, which was Islam. However, over time, they have been altered and lost, and what is left today of these religions is a mix of truth and falsehood. The only religion which has been preserved and preaches the same message brought by all prophets is the religion of Islam, the one true religion, which rules all sphere's of humans' lives, religious, political, societal, and individual, and it is upon all humans to investigate this religion, to ascertain its truth, and to follow it.