Well sure! Don’t get me wrong, it’s not that I don’t think this is important - “desire for the maintenance of arisen wholesome states, for their nondecay, increase, expansion, and fulfilment by development” is a part of right effort after all - I just don’t feel that this passage is saying that. Or at least, not only that perhaps.
Above Ven Dhammanando says that the ‘thought of metta’ presumably should be guarded as a mother her son. But this seems problematic to me.
The idea of ‘protecting’ metta seems strange to me. It’s not fitting with what I understand of metta and the nature of the mind. Because I think of protecting as guarding, concealing and holding something without wavering, and I don’t think of mind states like metta or even the thought of metta as something we can develop once, then it just stays there and we have to protect it. One is mindful, and ‘re-cultivates’ it, recollects it, throughout the day perhaps.
I use metta as my meditation object and it takes significant concentration and effort to generate and hold the feeling of strong metta (for me anyway ).
The idea of walking around all day doing that just feels comical to me because I wouldn’t get much else done. It’s like MN 19 on positive thoughts…
“As I abided thus, diligent, ardent, and resolute, a thought of non-ill will arose in me…a thought of non-cruelty arose in me. I understood thus: ‘This thought of non-cruelty has arisen in me. This does not lead to my own affliction, or to others’ affliction, or to the affliction of both; it aids wisdom, does not cause difficulties, and leads to Nibbāna. If I think and ponder upon this thought even for a night, even for a day, even for a night and day, I see nothing to fear from it. But with excessive thinking and pondering I might tire my body, and when the body is tired, the mind becomes strained, and when the mind is strained, it is far from concentration.’ So I steadied my mind internally, quieted it, brought it to singleness, and concentrated it. Why is that? So that my mind should not be strained.
Quite right, although in the example you give different actions are given for how the yogi should treat the mind, the simile is in regard to the spirit it is done in, it seems. For example, as you say, the yogi is not instructed to literally knead and sprinkle the mind with water, but with the same focus, thoroughness and completeness as the bathman, distribute rapture and pleasure throughout the body. Similarly, the simile is not instructing us to literally protect mind/metta as a mother, son, but to cultivate or spread the metta in as limitless and unstinting a manner.