Buddha was speaking about reality. Reality may be one, in its deepest essence, but Buddha also stated that all propositions about reality are only contingent. Reality is devoid of any intrinsic identity that can be captured by any one single proposition - that is what Buddha meant by "voidness." Therefore, Buddhism strongly discourages blind faith and fanaticism.
Dalai LamaIf you wish to experience peace, provide peace for another. If you wish to know that you are safe, cause another to know that they are safe. If you wish to better understand seemingly incomprehensible things, help another to better understand. If you wish to heal your own sadness or anger, seek to heal the sadness or anger of another.
Dalai Lama