Many thanks, Mike.
This list of what the spiritual life is not, reminds me of the list given in the Ratha-vinita Sutta (The Relay-Chariots).
"My friend, is the holy life lived under the Blessed One?"
"Yes, my friend."
"And is the holy life lived under the Blessed One for the sake of purity in terms of virtue?"[2]
"No, my friend."
"Then is the holy life lived under the Blessed One for the sake of purity in terms of mind [concentration]?"
"No, my friend."
"Then is the holy life lived under the Blessed One for the sake of purity in terms of view?"
"No, my friend."
"Then is the holy life lived under the Blessed One for the sake of purity in terms of the overcoming of perplexity?"
"No, my friend."
"Then is the holy life lived under the Blessed One for the sake of purity in terms of knowledge & vision of what is & is not the path?"
"No, my friend."
"Then is the holy life lived under the Blessed One for the sake of purity in terms of knowledge & vision of the way?"
"No, my friend."
"Then is the holy life lived under the Blessed One for the sake of purity in terms of knowledge & vision?"
"No, my friend."
"When asked if the holy life is lived under the Blessed One for the sake of purity in terms of virtue, you say, 'No, my friend.' When asked if the holy life is lived under the Blessed One for the sake of purity in terms of mind... view... the overcoming of perplexity... knowledge & vision of what is & is not the path... knowledge & vision of the way... knowledge & vision, you say, 'No, my friend.' For the sake of what, then, my friend, is the holy life lived under the Blessed One?"
"The holy life is lived under the Blessed One, my friend, for the sake of total Unbinding through lack of clinging."[3]
I suppose that there are many different ways of explaining what the spiritual life is not, depending on context. The difference here seems to be that the two highly advanced practitioners in dialogue in the Ratha-vinita Sutta (Sariputta and Mantaniputta) were warning about taking aspects or way-stations of the path for the entire path and goal, whereas the Brahmacariya Sutta seems much more black and white. Maybe it was delivered to those who had recently become monks. Or as a comment on some monks who had fallen short, perhaps.
I like the sequence of "restraint, abandoning, dispassion, and cessation", and can't find it repeated elsewhere. The final two of dispassion and cessation are often cited as supports for the seven enlightenment factors, along with seclusion, which does not feature here.