The response of the Angel Gabriel to Our Lady's question as to how what God proposed could come about is reflected in the Form of Life given by St. Francis to St. Clare which is why Pope John Paul II has said that the Annunciation contains the kernel of the Poor Clare vocation. The Angel's reply to Our Lady was:
"The Holy Spirit will come upon you, and the power of the Most High will cover you with its shadow. And so the child will be holy and will be called Son of God".
It is very similar to the kind of terminology used to describe manifestations of God in Scripture. For instance, in the Old Testament, the overshadowing with a cloud was the way that God manifested Himself. It also brings to mind the Transfiguration, where the disciples were enveloped within the cloud.
However, it is surprising that, while all the synoptic Gospels relate this incident, St. John, one of disciples present, makes no reference to it whatever. He was one of the privileged trio who were privy to some of the most intimate experiences of Jesus' earthly life. And of the ones of which we were aware, surely this must be one of the high points, certainly from an experiential point of view. Perhaps, for the supreme mystic of the apostles, it was just too intimate to verbalise.
In looking at this, it is striking, that in the case of the Incarnation, Our Lady too, was reticent about sharing this experience. It is generally believed that Our Lady herself was St. Luke's source for the accounts of the infancy narratives in his Gospel. However, while Our Lady told him about the Annunciation and even gave him the description quoted above of how the Incarnation would take place, we are not given an account of the actual event. We are told that the angel left her, but we are not told, what happened then. We are not told, for instance, what happened when the cloud overshadowed her (as we are in the Transfiguration accounts) and what she felt like. Surely it was too precious to articulate.
Given that the Gospels tell us that Our Lady pondered things in her heart, we can assume that this most wonderful of events was thoroughly reflected upon by her. We may not have her account of the Incarnation, but we do have her response, her great song of praise in the Magnificat. The exuberant joy of this canticle is the overflowing of her grateful heart. Having considered the significance of the Incarnation, she takes great delight in the reversals in the social order that result and particularly in the fact that such a thing could happen to a lowly soul like herself. She realises that it is all the Lord's doing and her response is total love and thanksgiving.
In St Clare, we realize that, in living a vocation epitomized by Our Lady in the Annunciation, she too has come to the same amazing discovery - that the Lord exalts the lowly, which is why she embraced poverty whole heartedly. It was not an end in itself, but a means to an end, that of living the Incarnation. All her letters reflect her ceaseless joy in this reality - that it is the poor and humble who are truly rich and beloved of God. And hers too, is a life lived in total gratitude. This is shown all through her life.
In what has come down to us of Clare's writings, we do not find her describing her mystical experiences, though we know from the testimonies at the process of canonisation that she had many. However, her letters and testament are like the Magnificat, in proclaiming with great joy how the Lord exalts the poor and lowly. It is the over spilling of her grateful heart. And, in the same way that Our Lady wanted to share her great joy with her cousin, we find the same eagerness in Clare's writings. Having herself felt what the friends of God feel, she urges us to "Gaze upon Him, consider Him, contemplate Him" as we "desire to imitate Him", so that we too may "taste the hidden sweetness" of God. Her dying words are simply a summary of the philosophy of her life of gratitude, "May you blessed Oh Lord, who have created me".
In imitation of Our Lady and St Clare, we too must become contemplatives of the heart, who ponder the wonders of the Lord in the inner sanctuary of our hearts and live out our lives in gratitude.