Majority of people  belong to a certain religion, accept its teachings, take ownership of the religion by birth and by the pronouncement of Kalima shahada, call him a  believer and label him a Muslim and consider all other children of God as different, inferior and separate

They follow the fundamental guidelines of their religion and start to divide, segregate and outcast people born to other faiths and show specialty and superiority

They Follow a religion based on their so called strong belief, religious knowledge, birth, sharia and sunnah

Man fail to realize that there is one wisdom and one single truth uniting all mankind
But variety of different ways of understandings, variety of expressions, variety of rituals
But one way of REALIZATION (annihilation of the false ego)

Most mankind think we are chosen and privileged to be born in a special religion and consider others not

Man fail to realize that all mankind are bonded by humanity and children of God (Allah)

However

A wise man (a man with wisdom) realizes that the fundamental basis of all religions and beliefs is one: Haqq, or one truth

The truth has always been covered by two garments. 
A turban on the head, and a robe upon the body 

The turban is made of mystery known as mysticism
And the robe is made of morality, which is called religion

Truth has been covered thus by most of the prophets and saints, in order to hide it from ignorant eyes, as yet too undeveloped to bear it in its naked form

Those who see the truth uncovered, abandon reason and logic, good and bad, high and low, new and old, differences and distinctions of names and forms fade away, and the whole universe is realized as nothing other than Haqq

Truth in its realization is one
in its representation it is many

Since its revelations are made under varying conditions of time and space

As water in a fountain flows in one stream but falls in many drops, divided by time and space

So are the revelations of the one stream of truth

Not everyone can easily comprehend the idea of different truths being derived from the one truth

Common sense has been so narrowly trained in this world of variety, that it naturally fails to realize the breadth and subtlety of a spiritual fact so far beyond the reach of its limited reasoning

The prophetic mission was intended to train the world gradually in divine wisdom according to its mental evolution and impart it to man, according to his understanding, in forms suitable to various lands at different periods, this is why numerous different religions are in existence, although the moral principles of all are the same