Christianity and Morals by Edward Westermarck

CHRISTIANITY is in the first place a religion but, as in the case of many other religions, it contains moral aspects closely connected with the purely religious ones.

The term religion has been used in many different senses, and it is therefore necessary that I should define what I mean by it. I take religion in the abstract, so to speak, as distinguished from any concrete religion, to be a belief in and a regardful attitude towards a supernatural being, on whom man feels himself dependent and to whom he makes an appeal in his worship. This definition seems to be in agreement with the most common usage of the word. It has been criticised on the ground that it would not apply to genuine Buddhism. But Buddhism was originally a metaphysical and ethical doctrine, which was transformed into a religion when the old gods of Brahmanism came back, when Buddha himself was deified, and Buddhism incorporated most of the local deities and demons of those nations it sought to convert.