"A word of prayer".
When a religious gathering is opened or closed, it is often said to do so with not simply a prayer, but "a word of prayer" as in "Let us begin with a word of prayer". I am interested in the origin of this construction, since it makes no grammatical sense. My guess is that it began as a half apologetic assurance that there would not be too many words, i.e. as saying "a brief prayer", but I wonder if there is an origin that can be traced beyond that. I have searched this site for any previous discussion of this, and found none, also nothing elsewhere on the web, although the phrase itself appears frequently.