Therefore, I say to you, the kingdom of God will be taken away from you and given to a people that will produce its fruit. (Mt 21,43)
This parable needs no explanation. It is very obvious that it speaks about God the Father, the people of Israel, leaders and prophets of Israel and Jesus the son. It is a straight run story until verse 41 of Matthew chapter 21.
After this, Jesus speaks about himself and the kingdom.
Kingdom will be taken away and given to others who will produce fruit. So the kingdom was among the people of Israel and it was within them. It is taken away from them because it has not produced fruit. Could we say that the kingdom will be with those who produce fruit? Fruit is the sign of the presence of the kingdom.
Jesus becomes the corner stone because he is the rejected stone. Again he is rejected by the people of Israel. This implies that Jesus came to the Israelites and they have rejected him.
There is a sort of parallel between Jesus and the kingdom. Jesus came to the people of Israel and the kingdom was within the people of Israel. Jesus is rejected and the kingdom is taken away from them.
So Jesus is the kingdom. Where Jesus is there the kingdom is.