Check out the first part of this video for the interview with Andy Naselli, who memorized the entire book of 1 Corinthians. He had been enlisted to write a commentary on 1 Corinthians by Crossway, but before writing a word he determined he wanted to truly know the book. He disciplined himself daily to work on this daunting challenge and in time, God helped him to commit the book to memory.
One of the most powerful services I have been a part of was last year when I heard him quote 1 Corinthians. There was no sermon per se, but the Word of God did the preaching as he quoted verse-by-verse through the book. I commend him for his discipline and faithfulness and want to thank him for his example which is both a rebuke and a challenge to me personally.
Source: Faithlife Today