The original question posed by the Pharisees was, "When is the Kingdom of God coming?" (verse 20). The long section from the end of verse 20 to verse 37 is Jesus' answer, first to the Pharisees (verses 20-21) and then to His disciples (verses 22-37). His reply to the Pharisees is rather curt: "You won't be able to discern the coming of the Kingdom because you haven't recognized that I am its chief representative, though I have been among you."
In His longer explanation to His disciples, Jesus goes into quite a bit more detail about the timing and conditions of establishing His Kingdom. First, He says, do not be deceived when people tell you Christ has come (verses 22-23). We will know very well when He returns; it will be like a flash of lightning that everyone will see (verse 24). However, before this can happen, Jesus must be tortured and crucified as man's Redeemer (verse 25). From our vantage point, which the disciples did not have, we know that this condition has already been met at Golgotha or Calvary.
Then He gives details about the conditions in the world when He returns. It will be as it was in the days of Noah and Lot (verses 26-30). He highlights two major signs of the end here:
1. He will come suddenly when people do not expect Him to return. Most people will be going about their normal activities, unaware of the times.
2. When He returns, society will be degenerate and wicked just as it was before the Flood came and before God destroyed Sodom and Gomorrah (see Genesis 6:5-7; 18:20; 19:1-11).
Luke 17:31-33 shows that, for His disciples, His coming will result in a test of faith. They will have to be willing to leave everything behind—their homes, their possessions, even their loved ones—in order to obey the call of God. Lot's wife turned back in longing for what she had left behind, and God's judgment fell swiftly upon her. We may have to be willing even to give up our lives for salvation, because in trying to save our physical lives, we would have to renounce our beliefs.
Verses 34-36 illustrate three scenes of judgment. These show that Christ will judge us individually, and despite how close we may be to another—a spouse, a neighbor, a co-worker—our obedience and good works will not deliver anyone else (see Ezekiel 14:12-20). We will have to prove ourselves to the righteous Judge of all (Acts 17:31; Romans 14:10).
Finally, the disciples ask Jesus where these things will take place (Luke 17:37). His reply is better translated in the Revised English Bible: "Where the carcass is, there will the vultures gather." This seems somewhat enigmatic, but if we take what He says literally, He implies that He will return at a place of great carnage. This would parallel the scenarios prophesied in Zechariah 14:1-5 and Revelation 19:11-21 (see especially verses 17-18, 21b).
All through this section Jesus is describing real circumstances, real people, and real places. He speaks of a literal Kingdom to be established at His return "with power and great glory" (Matthew 24:30).
Since the context of Luke 17:21 is Christ's second coming, and Jesus is speaking in great detail about the time, place, and conditions of His return, we must see His Kingdom as a literal government—just as real as any government of man. We cannot divorce "the Kingdom of God is among you" from this larger topic. Doing so distorts the true meaning of a literal, soon-coming Kingdom ruled by Jesus Christ that will grow to fill the whole earth after His return.
Richard T. Ritenbaugh
Is the Kingdom of God Within You?
Jesus draws on the stories of Noah and Lot to warn that, even though life seems to be relatively normal, when God brings the judgment, it will be sudden and complete. Because God is just, there will be indicators and warnings. But when He decides that the time is ripe for Him to intervene, it will happen with breathtaking speed. If we are warned to flee, we dare not linger or look back, like Lot's wife.
David C. Grabbe
Where the Eagles Are Gathered