"Therefore this saying went out among the brethren that that disciple would not die; yet Jesus did not say to him that he would not die, but only, “If I want him to remain until I come, what is that to you?” This is the disciple who is testifying to these things and wrote these things, and we know that his testimony is true. John 21:23-24
It may seem a small point to be accurate - but if we say something it must hold a true meaning else we are party to the very mistake that was reported in the churches at the time of John. Jesus didn't indicate that John would never die - some in the church did. John wrote this account so he corrected the error. What was true however, is that Jesus did tell Peter that John would not die until he returned or to use the Greek text:
εξηλθεν ουν ο λογος ουτος εις τους αδελφους οτι ο μαθητης εκεινος ουκ αποθνησκει και ουκ ειπεν αυτω ο ιησους οτι ουκ αποθνησκει αλλ εαν αυτον θελω μενειν εως ερχομαι τι προς σε ουτος εστιν ο μαθητης ο μαρτυρων περι τουτων και γραψας ταυτα και οιδαμεν οτι αληθης εστιν η μαρτυρια αυτου John 21:23-24
ἔρχομαι conjugated verb to come.
It matters because otherwise we are endlessly talking in circles. Even if we are free to do so.
Noted, but what I see is that Jesus didn’t confirm of deny that John would never die. The disciples inferred from His words, and rightly so in my opinion, that John would never die. I don’t see that John corrected the record in John 21 either like he didn’t outright confirm or deny what Jesus meant. That’s mysteriously open ended.
We are right to examine this text as a possible contender to substantiate the claims of Matthew 16:28; Mark 9:1; and Luke 9:27. Any other verses come to mind?