There is a sutra called the Parinirvana. It is concerned with the last three months of the life of the Buddha. It begins with a conversation in which the Buddha is obliquely giving advice to a politician who is considering going to war.
The first thing that we should take from this passage, therefore, is that political and religious affairs are not two watertight separate compartments. The Buddha is here dealing with an eminently worldly matter, namely war and peace.
When we look at the world today we see that far from bringing peace, as the Buddha attempted to do, religious differences often amplify community conflicts. This is due to a misunderstanding of Dharma.
In the course of the conversation, the Buddha has the following exchange with Ananda:
"What have you heard, Ananda: do the Vajjis show respect, honor, esteem, and veneration towards their shrines, both those within the city and those outside it, and do not deprive them of the due offerings as given and made to them formerly?"
"I have heard, Lord, that they do venerate their shrines, and that they do not deprive them of their offerings."
"So long, Ananda, as this is the case, the growth of the Vajjis is to be expected, not their decline.
Now we can assume that these shrines are not all Buddhist ones, especially as there is a reference to their traditional past. Perhaps none of them are, since we are still in the period of the Buddha's lifetime. It implies that the shrines are, indeed, a source of strength and cohesion to the community and give that community moral strength. This is good. The shrines of the Vajjis are probably different from those of neighbouring peoples. Each tribe has its identity expressed in its religious form.
These words of the Buddha tell us his attitude toward religious difference. He is not expecting everybody to be a Buddhist and he is acknowledging the value that diverse religious practices can bring. If we can value religious diversity as a treasure rather than a threat then it is possible to have peace in the world and growth is to be expected, not decline.
Clearly, the Buddha sees the value of social stability as well as of growth and change; of diversity as well as cohesion. The important thing is not to set these principles at war with one another but to proceed in a way that respects what is already good and adds what is better without prejudice. Harmony between religions is a key to world peace.