The Kingdom of God is the very livingness of life itself, as it endlessly and ceaselessly unfolds from one moment to the next. You live and move and have your very be-ing-ness in this kingdom. It is the very presence----indeed, omnipresence---of your life. If you want happiness, and peace of mind, and power to change the things in your life that you know need to be changed---and who doesn’t----the only 'place' (for want of a better word) where you can find those things is 'in' (that is, within) this kingdom.
Only a fool would seek to look for those 'things' (happiness, peace of mind, and personal power) elsewhere----but there are many such fools. Sadly, the churches are full of them. I say that not at all self-righteously, but I do say it with a certain anger, for I am sick and tired of conventional so-called ‘Bible-believing Christians’ distorting the simple message of Jesus and making silly and implausible claims for Jesus that he did not make for himself (for example, that he was God is a unique and exclusive sense) as well as for the Bible that the Bible does not make fot itself (for example, that the Bible is infallible and inerrant). I tell you this---there will be no peace in the world until that sort of thinking is thoroughly purged. For my part, for so long as there is breath in me, I will continue to rail against such 'thinking' and those who 'think' (ha!) such things.