In the context of Luke 21:5-19, how would you harmonize 16 and 18? If you take the figurative approach to 18, what do the hair and head represent? Literal? I look forward to your thoughts.
Luke 21 is a parallel account to Matthew 24 and Mark 13, discussing the fall of Jerusalem. In laying out the signs that will proceed the destruction of Jerusalem, Jesus warns that Christians would be put on trial and some would even be put to death.
"Then they will deliver you up to tribulation and kill you, and you will be hated by all nations for My name's sake. "And then many will be offended, will betray one another, and will hate one another" (Matthew 24:9-10).
"But watch out for yourselves, for they will deliver you up to councils, and you will be beaten in the synagogues. You will be brought before rulers and kings for My sake, for a testimony to them. ... But when they arrest you and deliver you up, do not worry beforehand, or premeditate what you will speak. But whatever is given you in that hour, speak that; for it is not you who speak, but the Holy Spirit. Now brother will betray brother to death, and a father his child; and children will rise up against parents and cause them to be put to death. And you will be hated by all for My name's sake" (Mark 13:9, 11-13).
"But before all these things, they will lay their hands on you and persecute you, delivering you up to the synagogues and prisons. You will be brought before kings and rulers for My name's sake. ... You will be betrayed even by parents and brothers, relatives and friends; and they will put some of you to death. And you will be hated by all for My name's sake" (Luke 21:12, 16-17).
There are two ways to look at Luke 21:18-19, "Yet not a hair of your head will perish. By your endurance you will gain your lives." "But he who endures to the end shall be saved" (Matthew 24:13; Mark 13:13).
Either Jesus is stating that despite the opposition, no real harm will come to the believer because the Father will grant him an eternal reward (Revelation 2:10; Hebrews 3:14; 10:39; Romans 2:7). It would be on the order of "In God I have put my trust; I will not be afraid. What can man do to me?" (Psalm 56:11).
Or, Jesus is stating that those who endure and survive through the persecutions before the fall of Jerusalem will also survive its destruction. "And He will send His angels with a great sound of a trumpet, and they will gather together His elect from the four winds, from one end of heaven to the other" (Matthew 24:31). "And then He will send His angels, and gather together His elect from the four winds, from the farthest part of earth to the farthest part of heaven" (Mark 13:27). The idea in this statement is that Jesus would send his angels to gather and protect his people from harm. Tradition states that no Christians died in the fall of Jerusalem because they heeded the signs and left before the Roman armies attacked.