Luke starts out his second narrative like a new driver adjusting the rearview mirror, remembering where we've come from in terms of Jesus' life, death, resurrection, and ascension. He reminds us of the promise of the Father, and gets us ready for the mission: Be My Witnesses. And then he ascends.
In this sermon from Luke 21:20-36, Jesus gives his disciples warnings about the temple and Jerusalem’s eventual destruction, and he also includes signs to look for as you watch for him to return.
Luke 21 opens with a small scene where Jesus notices a poor widow putting her last two coins in the offering at the temple, and it ends with Jesus' telling his disciples to be on guard as the end of days approaches, and the temple is destroyed