Charles Ellicott Commentary 1 Corinthians 15:11

"Whether then [it be] I or they, so we preach, and so ye believed." — 1 Corinthians 15:11 (ASV)

Therefore whether . . .—Better, Whether, therefore, it was I or they. Such (see 1 Corinthians 15:3–4) was and is our teaching; such was your belief. It does not matter from whom it came, whether from the greatest or least of the Apostles; the gospel was preached, and was accepted by you. These words thus recall the reader from the strong personal feeling shown in the preceding verse to the main argument.