The first reading gives us the prophet Joel's vision of the Last Judgement in the Valley of Jehoshaphat ("Yahweh judges"). Later Jewish tradition identified this with the Kidron Valley between Jerusalem and the Mount of Olives. While this identification has no basis in scripture, anyone who has ever visited the Holy Land can appreciate why the Jewish people made the connection. Standing on the Mount of Olives, one sees the ravine at the edge of the Holy City filled with tombs. It was the great burial site of Mount Zion, and the dead, buried in a standing position, are ready to rise again at the coming of the Lord as Judge "of all the nations".
The second reading gives us a new insight into the Last Judgement. Someone in the crowd calls out to Jesus, "Blessed is the womb that bore you, and the breasts that nursed you." After the infancy narratives of Matthew and Luke, this is one of the very few passages in the gospels that refer to Mary. And Jesus' reply is surprising, "No, rather, blessed is the one who hears the word of God and lives it." Mary is to be praised, not because she is the physical mother of Jesus, but (as Vatican II stressed) because she is His perfect disciple.
Putting the two readings together, we see that the basis of our salvation is not our claim to belong to the People of God (the Jewish nation, the Church), but our fidelity to the teaching and the example of Jesus the Lord.
Lord, bless me with the desire to do Your will.