The Beginning of Luke

What Luke writes here is an introduction or preface to the account of the Gospel he has written. And way this works is that you write your book first and then you write a preface or introduction. The very words Luke uses indicate that he is speaking of something that has already been written. These four verses may be the first four verses in the book of Luke but they are the last four verses written by Luke for this gospel. That means that everything else written in this account is to be understood in light of what Luke writes right here in these four verses.