One thing that Lewis Lancaster talked about in his lecture at Berkeley (see here) is that Buddhism is a “portable” religion. This means that Buddhism was the first “global” religion which was followed by Christianity. The core or the essence of Buddhism is not tied up with any particular place, or a race of people. Earlier religions, such as Brahmanism and Judaism, were very much tied up to particular places and people. You can’t become a Hindu; you have to be born one. That is, you have to have already a context in which you are a Hindu. You have to belong to a certain caste, and foreigners are always outside of the caste system. Hinduism, then, is not a proselytizing religion.
What interests Lancaster is that you can always take Buddhism with you, everything that enables you to set up and have a fully functioning religions practice and doctrines so that you can transplant the whole religion in a far away land. This is also in accordance with the teaching about no-self; there is no self, no core thing that one gets attached to. Buddhism in this sense does not have a core. Of course the Buddha said that there were important places for Buddhists to travel to in order to commemorate the Buddha’s time on this earth — his birthplace, the place where he attained Enlightenment, and so on. But those are not necessary for accomplishing the highest goal of the religion. For Hindus, on the other hand, the river Ganges is a “real” source of blessing. No other river can even come close. But there is no such river in Buddhism.
Another religion that is closely related to Buddhism, Jainism, has aboutthe same apparatus that could have made it as portable, but Jainism is not portable. This is not because of the doctrine in itself. There is no holy river in Jainism either. What has made Jainism much tied up with the land of India is instead its injunctions that the Jain monks may not make use of any vehicle. They have to walk wherever they want to go. So they cannot go far. This severely limits the range at which Jainism can fully spread.
Later religions, Christianity and Islam, all partake of this “portability” feature of Buddhism. You can have everything about Christianity without being tied up to, say, Jerusalem. All you need is a Bible and a set of practices. These practices even do not have to be exactly the same. As is the case in Buddhism, the practices serve to carry on the message of the religion, and they don’t have to be the same. All that matters is that they help to realize the purpose. For Buddhism, all you need is the set of the scriptures and a group of monks who follow the Vinaya rules. The monks are the ones who embody the teaching, so to speak. And even the monks themselves are not absolutely necessary, because one can gain Realization without becoming one. This is a rather controversial point, but even if the monks are necessary, one can become a monk only when certain minimal rules are followed. All this helped the spread of Buddhism far and wide.
What makes all this possible is the emphasis on the mind. And this shows how universal the religion really is. Since all of us possess our own individual mind and the capability of thinking and understanding, all of us have the potential to become fully realized. This is one of the important messages of the Buddha.