This is one of those quotations which turns up in all kinds
of contexts, ascribed to all kinds of characters and authors.
I have heard it used, for example, as a rallying cry in one
dramatized version of Alexandre Dumas's Three Musketeers. The
subject-matter of the quotation predisposes us to think of it
as coming from a great romantic - a Shakespeareian lover, say.
When we read that it is from Saint Augustine, the quotation
takes on a fresh allure, as we reflect on the implications on
how such words could emanate from one of the world's greatest
saints