"The kingdom of God is among you."

Holy Gospel of Jesus Christ according to Saint Luke 17:20-25.

Asked by the Pharisees when the kingdom of God would come, he said in reply, "The coming of the kingdom of God cannot be observed,
and no one will announce, 'Look, here it is,' or, 'There it is.' For behold, the kingdom of God is among you."
Then he said to his disciples, "The days will come when you will long to see one of the days of the Son of Man, but you will not see it.
There will be those who will say to you, 'Look, there he is,' (or) 'Look, here he is.' Do not go off, do not run in pursuit.
For just as lightning flashes and lights up the sky from one side to the other, so will the Son of Man be (in his day).
But first he must suffer greatly and be rejected by this generation.

Commentary of the day
Saint Isaac the Syrian (7th Century), monk near Mosul
Ascetical Discourses, 1st part

"The kingdom of God is among you."

The demons dread, but God and his angels desire the one who fervently seeks God day and night in his heart and repels far away the enemy's attacks. The spiritual country of this person who is pure in soul is within himself: the sun that shines within him is the light of the Holy Trinity; the air breathed by the thoughts within him is the holy Spirit, the Comforter; and the holy angels abide with him. Their life, their joy, their gladness is Christ, light of the Father's light. Such a one continually enjoys the contemplation of his soul, marvelling at the beauty he sees there, shining a hundred times more powerfully than the brightness of the sun.

This is Jerusalem. And it is «the Kingdom of God concealed within us», to use the Lord's own words. This country is the cloud of the glory of God into which only pure hearts can enter to behold their Master's face (Mt 5,8). Their understanding will be enlightened by the rays of his light.