If you argue that the human incarnation of your religion alone is correct, you will face the following powerful question:
Your human incarnation appeared in a particular region in a particular time only and gave the correct message to the people of that particular region only. After that, several generations passed before that particular message reaches the other regions of the world. All these generations missed that message and went to hell after death. If your message reached all the regions of the world in the beginning itself, at least some of the passed generations might have benefited. If your God alone created this entire earth and all this humanity is His issue, there should be no partiality in giving the message to one region only and allow other regions to be deprived of such fortune. This concludes that your God is partial to one region without reason or that your God did not create this entire humanity.
You have no answer for this question but we have the answer. Your God is impartial to all humanity and is the creator of this entire humanity. Even though the absolute God gave a particular message to a particular region through a particular human form, the same absolute God gave the same message in different human forms to other regions also. The language of the message may differ but the message is one and the same. The form, culture, dress etc., of the human incarnations in different regions may be different but the absolute God in these human incarnations is one and the same and hence His message is also one and the same delivered to all regions in the same time impartially.
Therefore, all the human beings are the children of the same God and hence there must be brotherly hood between all the human beings.