Kingdom life in a fallen world

Sinclair Ferguson on the kingdom of God and the Sermon on the Mount:

A paradox lies at the heart of the kingdom.  On the one hand it has already come near (Matt. 4:17, 23)...But in another sense, it is still to come.  That is why Jesus teaches us to pray to God, 'Your kingdom come' (6:10).  How can the kingdom be here, and yet lie in the future?   

[...]

The kingdom of God has come, in Jesus.  Through faith in him, we enter the kingdom.  It belongs to us.  But we live in 'the kingdom of the world' (Rev. 11:15), although we do not belong to it.  We belong to a new order of things, a new age altogether, a new humanity in Christ.  But that new life has to be lived out within the context of the old. 

[...]

That kingdom will be consummated only when Christ returns and transforms the kingdom of this world into his own kingdom, publicly putting everything under his authority.  But the Sermon on the Mount is not about there and then; it is about here and now.  It its not asking us whether we will live a Christlike life in heaven.  It is calling us to lead that life on earth, as Jesus himself did to perfection.  It is not a sermon about an ideal life in an ideal world, but about the kingdom life in a fallen world.  

How do you react?

Sinclair Ferguson, The Sermon on the Mount, pp. 7-8, 10.