Jesus told his disciples a parable.
“Consider the fig tree and all the other trees.
When their buds burst open,
you see for yourselves and know that summer is now near;
in the same way, when you see these things happening,
know that the Kingdom of God is near.
Amen, I say to you, this generation will not pass away
until all these things have taken place.
Heaven and earth will pass away,
but my words will not pass away.”
21:31. The Kingdom of God, announced by John the Baptist (cf. Mt 3:2) and described by our Lord in so many parables (cf. Mt 13; Lk 13:18–20), is already present among the apostles (Lk 17:20–21), but it is not yet fully manifest. Jesus here describes what it will be like when the Kingdom comes in all its fullness, and he invites us to pray for this very event in the Our Father: “Thy Kingdom come.” “The Kingdom of God, which had its beginnings here on earth in the Church of Christ, is not of this world, whose form is passing, and its authentic development cannot be measured by the progress of civilization, of science and of technology. The true growth of the Kingdom of God consists in an ever deepening knowledge of the unfathomable riches of Christ, in an ever stronger hope in eternal blessings, in an ever more fervent response to the love of God, and in an ever more generous acceptance of grace and holiness by men” (Creed of the People of God, 27). At the end of the world everything will be subjected to Christ and God will reign for ever more (cf. 1 Cor 15:24, 28).
21:32. Everything referring to the destruction of Jerusalem was fulfilled some forty years after our Lord’s death—which meant that Jesus’ contemporaries would be able to verify the truth of this prophecy. But the destruction of Jerusalem is a symbol of the end of the world; therefore, it can be said that the generation to which our Lord refers did see the end of the world, in a symbolic way. This verse can also be taken to refer to the generation of believers, that is, not just the particular generation of those Jesus was addressing.
Friends, in today’s Gospel passage Jesus speaks of the time when the plan of God will be fulfilled. Some philosophies defend a circular or cyclic understanding of time: that time just continually circles back on itself, repeating itself like the cycles of the seasons. The modern philosopher Nietzsche spoke of the “eternal return of the same.” That’s a mythic consciousness, and it can be found all over the world.
But Jews had a very different sense of time, what we might call “linear.” They felt that time was moving somewhere, that it had, under God’s direction, a purpose. The past was not simply there to be repeated endlessly; rather, the past was a preparation for a definitive future. It was an anticipation of what God would do, what God was going to accomplish.
So, the Lord assures us that the Kingdom of God is near and that we must prepare for its coming.
– Bishop Robert Barron
May the virtues of faith, hope, and love go with you today – DV.
 Saint Luke’s Gospel, The Navarre Bible (Dublin; New York: Four Courts Press; Scepter Publishers, 2005), 172–173.