1 Corinthians 15:11

Therefore whether it were I or they, so we preach, and so ye believed (KJV)

Then: This is the end of a review of what's known about appearances of the resurrected Christ. Paul summarizes that and adds it doesn't make any difference who is preaching. They all preach the resurrected Christ, and everyone hearing the letter now believes.

Now: Just like the Corinthians, we are warned Paul is moving on to a different point.