C.K. Barrett, "Acts and the Church Today, Pt. 4" accessed here.
"...as others have said...being a pastor, being a preacher involves theology. You cannot be a pastor or a preacher without theology....Church History, after all is only the account of the way in which the Church was doing its pastoral job yesterday. We're doing it today. Church History is the way it was being done yesterday and the day before yesterday."
In context, Barrett is speaking of Luke as historian and theologian and how theology is practical and pastoral. Therefore, Luke's practical and pastoral aims in Luke-Acts are theological.