What does Luke 21:19 mean?

The disciples have learned, from Jesus, that the temple will be destroyed. The disciples ask when this will happen. In response, He gives an overview of hardships which will occur during the church age (Luke 21:8–11), then specifies three events that will particularly affect Jews. First is persecution of the disciples (Luke 21:12–19). Second is the fall of Jerusalem by the Romans in AD 70 (Luke 21:20–24). Last is the day of the Lord when Jesus will return and redeem the Jews (Luke 21:25–28).

Here, Jesus finishes His description of the persecution the disciples will face with some encouragement. All is not lost. They will survive. Like the previous verse, this one is confusing if read without context. It seems to say that the disciples will not die if they endure persecution. The meaning hinges on the terms "endurance" and "lives." Does endure mean not run away from persecution? Or to stay tough during persecution? Or to stay faithful to Jesus during persecution? Does "lives" mean physical lives or resurrection lives?

It obviously doesn't mean that the disciples' physical lives can be saved if they endure persecution; Jesus has just said some will be killed (Luke 21:16). So, "lives" clearly refers to eternal life. If "endurance" means that a Jesus-follower will never deny Jesus in a moment of weakness or misrepresent Him through ignorance, then Peter and Apollos wouldn't be saved (Luke 22:54–62; Acts 18:24–26).

So, what is the verse saying? Reading it within context, it's clear. It's not meant to be a theological statement about the nature of salvation or the perseverance of the saints. It's meant to be encouragement and exhortation. Persecution will come. Don't despair. Don't be afraid. Keep your focus on Jesus. Eternal life is coming.