Here is what Augustine took Jesus to mean about death in John 8:51 – “Amen, amen, I say to you, whoever keeps my word will never see death”:
“See” and “taste” here are used in the sense of what is really the case, that is, what someone will know by experience. And since Jesus was about to die himself, this is how he spoke with those about to die. … But what does this mean, “If anyone keeps my word, he will never see death”? It means nothing less than he saw another death from which he came to free us — the second death, eternal death, the death of hell, the death of the damned, which is shared with the devil and his angels! This is real death; the other kind of death is only a passage.