What does Luke 4:21 mean?

The Scripture Jesus has just read is from the prophet Isaiah (Luke 4:17–19). This included predictions of Messiah's healing, rescue, and good news (Isaiah 61:1–2). The passage also describes God's impending judgment on sin. However, Jesus stopped before reading that part. Now, after declaring God's promise to send a saving, healing Anointed One, Jesus claims the prophecy is being fulfilled.

Jesus separates the work done by the Messiah in His first coming from the work done in His second coming. Jesus' first arrival on earth was in humble circumstances (Luke 2:6–7), focused on securing salvation for mankind (John 3:16–18). His second coming will be in awesome power, focused on delivering God's wrath on an evil world (Revelation 19:11–16).

The people will understand that Jesus means that He, Himself, is the fulfillment of this prophecy. Jesus is not simply declaring that the Savior is somewhere in the world. Rather, He implies that He is the One predicted by Isaiah. The people will react with a combination of amazement and skepticism (Luke 4:22). Much of this is due to knowing Jesus as a child—this is His hometown synagogue (Luke 4:16) and the people struggle to see Jesus as anything more than a poor Nazarene.