“Whoever prays for the coming of the kingdom of God within himself is praying rights, praying for the kingdom to dawn in him, bear fruit and reach perfection. For God reigns in every saint, and every saint obeys God’s spiritual laws – God, who dwells in him just as He dwells in any well-ordered city. The Father is present in him and in his soul Christ reigns alongside the Father, as it is said: ‘We will come to him and make Our dwelling within him.”
“There is something important we need to understand about the kingdom of God: just as righteousness has no partnership with lawlessness, just as light has nothing in common with darkness and Christ has no agreement with Belial, so the kingdom of God and the kingdom of sin cannot co-exist. So if we want God to reign within us . . . let us be made fruitful by the Spirit. Then we will be a spiritual garden of Eden for God to walk in . . . Let us pray to our Father in heaven: hallowed be Thy Name, Thy Kingdom come” (Origen, from A discourse on prayer).