I'd guess it's a convention of that society, and means no more than our (peculiar, in my view) manner of the writing of some letters starting "Dear Sir" and end

I'd guess it's a convention of that society, and means no more than our (peculiar, in my view) manner of the writing of some letters starting "Dear Sir" and ending "I remain faithfully yours ...", or similar words. I think this may be a register (https://en.wikipedia.org/wiki/Register_%28sociolinguistics%29 https://en.wikipedia.org/wiki/Register_%28sociolinguistics%2...)