The two central sculptural figures of the swooning nun and the angel with the spear derive from an episode described by Teresa of Avila, a mystical cloistered Discalced Carmelite reformer and nun, in her autobiography, The Life of Teresa of Jesus (1515–1582).
Her experience of religious ecstasy in her encounter with the angel is described as follows:
I saw in his hand a long spear of gold, and at the iron's point there seemed to be a little fire.
He appeared to me to be thrusting it at times into my heart, and to pierce my very entrails; when he drew it out, he seemed to draw them out also, and to leave me all on fire with a great love of God.
The pain was so great, that it made me moan; and yet so surpassing was the sweetness of this excessive pain, that I could not wish to be rid of it.
The soul is satisfied now with nothing less than God.
The pain is not bodily, but spiritual; though the body has its share in it.
It is a caressing of love so sweet which now takes place between the soul and God, that I pray God of His goodness to make him experience it who may think that I am lying.

The group is illuminated by natural light which filters through a hidden window in the dome of the surrounding aedicule, and underscored by gilded stucco rays.
Teresa is shown lying on a cloud indicating that this is intended to be a divine apparition we are witnessing.
Other witnesses appear on the side walls; life-size high-relief donor portraits of male members of the Cornaro family, e.g. Cardinal Federico Cornaro and Doge Giovanni I Cornaro, are present and shown discussing the event in boxes as if at the theatre.
Although the figures are executed in white marble, the aedicule, wall panels and theatre boxes are made from coloured marbles.
Above, the vault of the Chapel is frescoed with an illusionistic cherub-filled sky with the descending light of the Holy Ghost allegorized as a dove.

The art historian Rudolf Wittkower wrote:
In spite of the pictorial character of the design as a whole, Bernini differentiated between various degrees of reality, the members of the Cornaro Chapel seem to be alive like ourselves.
They belong to our space and our world.
The supernatural event of Teresa's vision is raised to a sphere of its own, removed from that of the beholder mainly by virtue of the isolating canopy and the heavenly light.
The two central sculptural figures of the swooning nun and the angel with the spear derive from an episode described by Teresa of Avila, a mystical cloistered Discalced Carmelite reformer and nun, in her autobiography, The Life of Teresa of Jesus (1515–1582). Her experience of religious ecstasy in her encounter with the angel is described as follows:
I saw in his hand a long spear of gold, and at the iron's point there seemed to be a little fire. He appeared to me to be thrusting it at times into my heart, and to pierce my very entrails; when he drew it out, he seemed to draw them out also, and to leave me all on fire with a great love of God. The pain was so great, that it made me moan; and yet so surpassing was the sweetness of this excessive pain, that I could not wish to be rid of it. The soul is satisfied now with nothing less than God. The pain is not bodily, but spiritual; though the body has its share in it. It is a caressing of love so sweet which now takes place between the soul and God, that I pray God of His goodness to make him experience it who may think that I am lying.
The group is illuminated by natural light which filters through a hidden window in the dome of the surrounding aedicule, and underscored by gilded stucco rays. Teresa is shown lying on a cloud indicating that this is intended to be a divine apparition we are witnessing. Other witnesses appear on the side walls; life-size high-relief donor portraits of male members of the Cornaro family, e.g. Cardinal Federico Cornaro and Doge Giovanni I Cornaro, are present and shown discussing the event in boxes as if at the theatre. Although the figures are executed in white marble, the aedicule, wall panels and theatre boxes are made from coloured marbles. Above, the vault of the Chapel is frescoed with an illusionistic cherub-filled sky with the descending light of the Holy Ghost allegorized as a dove.
The art historian Rudolf Wittkower wrote:
In spite of the pictorial character of the design as a whole, Bernini differentiated between various degrees of reality, the members of the Cornaro Chapel seem to be alive like ourselves. They belong to our space and our world. The supernatural event of Teresa's vision is raised to a sphere of its own, removed from that of the beholder mainly by virtue of the isolating canopy and the heavenly light.
Ecstasy of Saint Teresa