“To the question ‘What is Romans all about?’ a variety of answers might be given. . . . An interesting point emerges if we approach the epistle statistically. . . . It comes as no surprise that the word Paul uses most frequently is some form or other of the definite article (1105x). Nor that this is followed in order by [“and”] (274x), [“in”] (172x) and [“he”] (156x). These are all common words and are bound to occur frequently. But not everybody would expect that Paul’s next most frequent word in this epistle is “God,” which is found no less than 153x. We may gauge something of the significance of this by noting that even some very common words do not occur as often. Thus [“but, however”] is found but 147x, the verb [“to be”] in its various forms 113x, and the preposition [“into”] 119x. . . . It is clear that in Romans Paul speaks of God so often that no other subject comes even remotely near it.”
Leon Morris, “The Theme of Romans,” in W. Ward Gasque and Ralph P. Martin, editors, Apostolic History and the Gospel (Exeter, 1970), pages 249-250.