The following is from John Paul II's 1997 apostolic letter Divini Amoris Scientia, in which he declared Therese a Doctor of the Church.
"The core of her message is actually the mystery itself of God-Love, of the Triune God, infinitely perfect in himself. If genuine Christian spiritual experience should conform to the revealed truths in which God communicates himself and the mystery of his will (cf. Dei Verbum, n. 2), it must be said that Thérèse experienced divine revelation, going so far as to contemplate the fundamental truths of our faith united in the mystery of Trinitarian life. At the summit, as the source and goal, is the merciful love of the three Divine Persons, as she expresses it, especially in her Act of Oblation to Merciful Love. At the root, on the subject's part, is the experience of being the Father's adoptive children in Jesus; this is the most authentic meaning of spiritual childhood, that is, the experience of divine filiation, under the movement of the Holy Spirit. At the root again, and standing before us, is our neighbour, others, for whose salvation we must collaborate with and in Jesus, with the same merciful love as his.
Through spiritual childhood one experiences that everything comes from God, returns to him and abides in him, for the salvation of all, in a mystery of merciful love. Such is the doctrinal message taught and lived by this Saint.
As it was for the Church's Saints in every age, so also for her, in her spiritual experience Christ is the centre and fullness of Revelation. Thérèse knew Jesus, loved him and made him loved with the passion of a bride. She penetrated the mysteries of his infancy, the words of his Gospel, the passion of the suffering Servant engraved on his holy Face, in the splendour of his glorious life, in his Eucharistic presence. She sang of all the expressions of Christ's divine charity, as they are presented in the Gospel (cf. PN 24, Jésus, mon Bien-Aimé, rappelle-toi!).
Thérèse received particular light on the reality of Christ's Mystical Body, on the variety of its charisms, gifts of the Holy Spirit, on the eminent power of love, which in a way is the very heart of the Church, where she found her vocation as a contemplative and missionary (cf. Ms B, 2r·-3v·).
Lastly, among the most original chapters of her spiritual doctrine we must recall Thérèse's wise delving into the mystery and journey of the Virgin Mary, achieving results very close to the doctrine of the Second Vatican Council in chapter eight of the Constitution Lumen gentium and to what I myself taught in the Encyclical Letter Redemptoris Mater of 25 March 1987."
O Lord, You have said: Unless you become as little children you shall not enter the kingdom of heaven; grant us, we beg You, so to follow, in humility and simplicity of heart, the footsteps of the Virgin blessed Thérèse, that we may attain to an everlasting reward. Amen.St. Therese, pray for us!