Why is this the first time Jesus is quoted chronologically in Scripture?
This is the first time Jesus is quoted chronologically because the Gospels had not yet been written. Paul wrote to the Corinthians the very same words before the Gospel accounts existed, so the revelation came directly to him rather than through Matthew or the other Gospel writers.
Les explains that one commentator notes this is probably the first time Jesus is quoted chronologically in the Scriptures, because the Gospels hadn't been written yet. Paul couldn't delve back to Matthew or one of the other writers and say this came by revelation. Les points out that God does everything in His own order: before the Gospels were ever written, Paul writes to the Corinthians the very same words. This occurs in the context of explaining the Lord's Supper, which is a constant reminder of the finished work of the cross, and Paul provides the doctrinal reason for it in 1 Corinthians 11:26.