Yet have I sent the brethren, lest our boasting of you should be in vain in this behalf; that, as I said, ye may be ready:
Have I sent. We should say, 'I send;' the ancients put it in the past, as it would be by the time that the letter arrived.
The brethren (2 Corinthians 8:18; 2 Corinthians 8:22) - Titus and the two others.
Should be in vain in this behalf - `should be proved futile in this particular,' however true in general (2 Corinthians 7:4). A tacit compliment, softening the monition.
As I said - as I was saying (2 Corinthians 9:2).