It is an apostolic response to ethnic problems in those churches, and it is a “bread-and-butter” letter written in advance of his arrival, seeking support for his mission to Spain.I raised a couple of questions about it, first the appropriateness of the term "bread-and-butter letter" and second the matter of where the quotation is from. I had copied out the quotation some years ago but somehow managed to lose the citation. In yesterday's class on the Life and Letters of Paul, I returned to the Epistle to the Romans and again mentioned this quotation. Happily, Ken Olson managed to find it for me, and it looks like something had happened in my transcription of the quotation. Here it is with a proper citation:
A crisis brought most Pauline letters into existence. Even Romans, written to a church that Paul’s preaching did not establish, is a “bread-and-butter” letter written in advance of his journey, seeking support for his mission to Spain (cf. 15:22-24). Ephesians, however, lacks clues concerning a concrete crisis or occasion.
J. Paul Sampley, “The Letter to the Ephesians”, in Gerhard Krodel (ed.), Ephesians, Colossians, 2 Thessalonians, The Pastoral Epistles (Proclamation Commentaries; Philadelphia: Fortress, 1978): 9-39 (9)