I think that means "who is this message"?

I think it would be "Pour qui est ce/le (this/the) message?"

__________________
DAVIDIVS DOCTVS VTRIVSQVE LINGVAE
Husband of Emilia
Member: First Reformed Presbyterian Church of Durham (RPCNA) - Durham, NC
Currently in the process of transferring membership to an as-yet-undecided church in Chapel Hill
Student: University of North Carolina at Chapel Hill, German Literature and Classics