This article with its Hebrew Language analysis will be difficult for many laymen to follow. Here is the upshot: The earliest witness to Is. 53.9 comes from The Great Isaiah Scroll, the only virtually complete book of the bible found as part of The Dead Sea Scrolls. This text is between 950 and 1150 years older than our previous earliest record: the Leningrad Codex of about 1000 A.D.
The Dead Sea Texts’ reading gives the rationale for Paul’s statement in 1Cor. 15.3-4. The Pauline Era was not very far removed, or even overlapped, from the scroll production occurring in the Qumran Community. Therefore, it is plausible that Paul’s “Isaiah” text was identical to Qumran’s copy which preserved the original reading. This reading has a more credible standing being closer in time to the original production.
Gentry’s argument can still be followed without knowing the biblical languages he references. I have just summarized his conclusion. I found his article very helpful in making sense of Paul’s proofs. Jesus really died and was buried just like most Christians will be. Jesus however, conquered death for us mortals giving us a sure hope of eternal life with Him. This is the content of the Gospel (1Cor. 15.1-4).Part 3: The Servant’s Burial according to the Scriptures