I am reading "Psychology and Religion" which is a transcribed lecture by Carl Jung. In this lecture he mentions several times how the psyche uses dogma and ritual to defend again original religious experience or as a substitute. I understand why we might want to substitute for original religious experience, but I don't see where he talks about why we would defend against it. What is Jung's opinion on why we need to defend against original religious experience?
For a really quick and clear understanding of why sometimes it is better to stay in the container of dogma read Edward Edinger's Moby Dick.
Jung's position is that religious energy must only sometimes be defended against. The entire process of Jungian Analysis does, in fact, consist of a process of contacting one's own religious experience in a first-hand, non-dogmatic (responsible, discriminated) way. This process is what Jung developed and described in the Red Book and consists of analyzing one's dreams (which are essentially products of religious experience) active imagination, and discovering the religious energies in one's own, individual psyche. However, Jung said in many places that Analysis was not for everybody, and if you can stay in the "container" of dogma contentedly, do so. He advocated Analysis only when your religious container was broken and neurotic symptoms where beginning to appear. I.e., those for whom the old dogmas would no longer work.
To understand the power of the psyche's religious function, consider St. Paul's experience on the road to Damascus. He was knocked off his horse and went temporarily blind from having a religious experience (i.e., moving from persecuting Christians, to suddenly being converted to a Christian.) Similarly, think of Islamic religious fundamentalism; here is an example of religious energy coming up in raw form. It's not that that energy is "bad;" it is that it has not been reflected upon by the ego, the conscious mind, in a modern way, and the energy coming from the religious function is not "channeled," or "well-contained."
Consider also the numerous cults gone awry: Jamestown, Nazism, etc. The appendix in Edinger's book The New God Image is worth studying here. If that's the best you can do with your religious energy, better to stay in dogma. . . .
Jung frequently establishes his point of view by reviewing what others have thought and done in history. He does this to show that there is a psychological necessity and historical precedent for what he is saying. The repression or suppression of the individual religious experience has been the historical position of much organized religion, particularly Christianity, for millennia. The Catholic position has been that all believing Catholics need to "adopt the official dogma" (only Jesus and a few saints get to have a first-hand, non-dogmatic experience.) So Jung is just saying that throughout history, the need to contain religious energy in something has been found to be a necessity. (Esther Harding's Psychic Energy: It's Source and Transformation is particularly clear on this.)
See also Edward Edinger's many other books on this topic, for instance