Hermes Trismegistus, also known as the Egyptian god Thoth, is said to be the author of the Corpus Hermeticum, a series of instructional fragments of sacred esoteric teachings used and studied through the ages by various initiates and mystery schools.
In Poimandres, The Vision of Hermes, the following two separate passages indicate the use of out-of-body experiences (OBEs) for accessing the mysteries, or esoteric teachings, and guidance:
“Hermes, while wandering in a rocky and desolate place, gave himself over to meditation and prayer. Following the secret instructions of the Temple, he gradually freed his higher consciousness from the bondage of his bodily senses; and, thus released, his divine nature revealed to him the mysteries of the transcendental spheres.”
“In concluding his exposition of the Vision, Hermes wrote: “The sleep of the body is the sober watchfulness of the Mind and the shutting of my eyes reveals the true Light. My silence is filled with budding life and hope, and is full of good.”
~ The Secret Teachings of All Ages, Manly P. Hall, Poimandres, The Vision of Hermes (source).
Note that in the first quote above, though it does not reveal “the secret instructions of the temple,” it talks about giving oneself over to meditation and prayer in order to gain an out-of-body experience for learning. For more examples of exercises for out-of-body experiences and learning from dreams see here and here.