"The passage that follows ( 2 Corinthians 2:14 to 2 Corinthians 7:4) is the longest coherent section within2Corinthians and Isaiah , arguably, the centerpiece of the entire letter. Nonetheless, it is not freestanding, but continuous with what precedes it." [1][source]
Paul"s recollection of his happy reunion with Titus in Macedonia and the good news his friend brought from Corinth triggered the following "great digression." The Corinthians, Paul learned, had responded favorably to the "severe letter." The apostle viewed their response as a divine vindication of his apostleship and a triumph of divine grace in the Corinthians" hearts. [source][source][source]
". . . 214-74is a lengthy digression on Paul"s part, caused by the contrast between the agitation of mind which he has just described and his present sense of relief and rejoicing." [2][source]
". . . one thought leads on to another in an outpouring of spiritual wealth unsurpassed in any other of his epistles." [3][source]