Jesus tells the Pharisees that “the kingdom of God is within you” (Luke 17:20-21). Barclay (1975) has two interpretations of this passage. The first is a “revelation in the hearts of men” (p 220). The second is that “the kingdom of God is among you” (p 220). It is the first interpretation that carries the most meaning for me and that I seek to communicate with others.
It seems to have immediate application if we take the kingdom as being in the hearts of men. If the kingdom of God reigns in our hearts then we will have less concern about some future coming. We will find an inner peace despite the outer turmoil. The kingdom of God brings change to a person in the same way that yeast ferments dough and salt brings flavour to food. If God's kingdom reigns in us then what happens around us will be less of a problem. Our attitudes and our way of living will work from within to bring us peace and confidence.
Will we cry how long before his return, when we know God's inner peace? Will we want to do anything other than focus on what God wants us to do if we already experience His kingdom within?
Speculation about the second coming only makes sense if we are not working to make His kingdom known to others. We have to work in the confidence that He is working out His will for us even if it isn't happening at the rate that we might hope for.
Barclay, W. (1975). The gospel of Luke (revised ed.). Edinburgh: The Saint Andrew Press.