Pope John Paul II sees the mystery of the Annunciation as central to the understanding of our Poor Clare charism and mystical motherhood is, the conceiving of Christ in the soul, so that we may be life-giving channels of His grace.
St Clare & St Bonaventure insist that this can only happen in a faithful soul.
Even in the 2nd century, St. Irenaeus had seen these words as a proclamation of the "generation of Christ from the virgin". For this reason, especially in the last part, the Psalm is reread by Christian tradition in terms of Christmas, and the Word becoming flesh, and so it ties in very much with the mystery of the Annunciation. The Holy Father, when commenting on this psalm, tells us that when justice is spoken of in the Bible, it means salvation and holiness. St. Therese equates God's justice with His mercy, so all of these words are interchangeable in this psalm.
"Mercy & faithfulness have met, justice & peace have embraced."
These are wonderful lines! They conjure up a beautiful meeting, almost a romantic rendezvous! Further on in the psalm, we are told that 'faithfulness shall spring from the earth' and 'justice look down from heaven'. So, when we hear that mercy and faithfulness have met and embraced, it is as if the Lord looks lovingly on the faithful one, whose fidelity and love He cannot resist, and plunges down to embrace her and envelop her with His mercy. It is like a scene from the 'Song of Songs'! We are told that the earth will yield it's fruit, and how could it not - how could the faithful soul not be fruitful after being wrapped in the embrace of mercy?
Our Lady is our model in this fidelity, as she was for St. Clare. It was her faithfulness in the small things in her life that prepared her to say the big "Yes" when it was asked of her. It is the same in our lives. We may not feel that some things are important - they are too small to make any difference, and yet, it is fidelity to the small things that made such a great saint of St. Therese. And our faithfulness in small things broadens our perspectives and allows God's grace and mercy to come to embrace us. It is our fidelity that attracts God to us, and causes the "earth to yield its fruit" in us. His strength is visible in our faithful littleness, and is the source of our fruitfulness. This is why St. Clare says that we can carry Him spiritually in our bodies, by following His footprints of humility and poverty.