20-21 Being asked by the Pharisees when the kingdom of God would come, Jesus answered them,  “The kingdom of God is not coming with signs to be observed, nor will they say, ‘Look, here it is!’ or ‘There!’ for behold, the kingdom of God is in the midst of you.” 22-25 And he said to the disciples, “The days are coming when you will desire to see one of the days of the Son of Man, and you will not see it. And they will say to you, ‘Look, there!’ or ‘Look, here!’ Do not go out or follow them. For as the lightning flashes and lights up the sky from one side to the other, so will the Son of Man be in his day.  But first he must suffer many things and be rejected by this generation. 

26-30 Just as it was in the days of Noah, so will it be in the days of the Son of Man. They were eating and drinking and marrying and being given in marriage, until the day when Noah entered the ark, and the flood came and destroyed them all.  Likewise, just as it was in the days of Lot - they were eating and drinking, buying and selling, planting and building,  but on the day when Lot went out from Sodom, fire and sulphur rained from heaven and destroyed them all - so will it be on the day when the Son of Man is revealed. Luke 17:20-31 English Standard Version

God's Kingdom is different to the empires of the world! It doesn't arrive with the visible signs of pomp, parades, armies, Kings and Presidents that we are familiar with. That’s what the Pharisees were most likely looking for. What's the first point Jesus made about God's Kingdom in vs 20-21?

Those words could refer to the fact that God's Kingdom is when He reigns in the hearts of men and women rather than over some country. But they could also be referring to Himself. In the person of Jesus Christ God's Kingdom was already in their midst – they just didn't realize that. The reason I say this is because of what follows in vs 22-25. After Jesus ascended to heaven many people would long to see even one of the days when He had been amongst them. This longing and uncertainty happened. The apostle Paul wrote to Christians in Thessalonica about this subject and said: “Let us clarify some things about the coming of our Lord Jesus Christ and how we will be gathered to meet him. Don’t be easily shaken or alarmed by those who say that the day of the Lord has already begun. Don’t believe them, even if they claim to have had a spiritual vision, a revelation, or a letter supposedly from us. Don’t be fooled by what they say. For that day will not come until there is a great rebellion against God and the man of lawlessness is revealed.” (2 Thessalonians 2:1-3)

What Paul said ties in with what Jesus said in vs 22-25. Just as you can't hide an enormous flash of lightning – so everyone will know when Christ returns! But His return and the revelation of God's Kingdom would be preceded by a time of suffering and rejection. Calvary still lay ahead of Him. What was the solemn warning Jesus gave in vs 26-30 about the question of 'when will the Kingdom of God come'?

Many people will be taken by complete surprise and totally unprepared! Jesus gave two vivid examples of what it will be like when He is revealed – no longer as the suffering servant, but as the King of glory. But it shouldn't be a surprise for Christians. The apostle Paul also said to the Christians in Thessalonica: “Now concerning how and when all this will happen - you know quite well that the day of the Lord’s return will come unexpectedly, like a thief in the night. When people are saying, 'Everything is peaceful and secure,' disaster will fall on them as suddenly as a pregnant woman’s labour pains begin. There will be no escape. But you aren’t in the dark about these things, and you won’t be surprised when the day of the Lord comes like a thief. For you are all children of the light and of the day; we don’t belong to darkness and night. So be on your guard, not asleep like the others. Stay alert and be clearheaded.” (1 Thessalonians 5:1-6) Words we should daily take to heart for ourselves as well.