What is this knowledge of religion? In its fullest sense it is nothing but knowledge of God. Without knowledge of God there is no knowledge of religion. There may be belief in religion but there is not knowledge of religion. Until there has been the personal experience and contact such that the mind has grasped its significance, it cannot be called knowledge. Certainly when another has learned it, it is not one's knowledge. But when it has become part of one's own life, it is one's knowledge.
Now this knowledge of God, how does it bring tolerance? It brings tolerance because it makes one see all and know all. If it does not make one see all and know all it is not knowledge of God. The God of popular religion is that name given to the human thought-concept of Divinity, but that human thought-concept is not the Reality. It is the Reality which, when apprehended, causes this condition of universal beneficence and compassion toward all creatures. That is why Allah is called Er-Rahman, Er-Rahim.