Thanks to the "research online" site of the University of Note Dame of Australia, I am happy to invite you to read at http://researchonline.nd.edu.au/theses/42 this excellent paper published in 2006.  It links the development in Therese's understanding of mission to the challenge of the Church's mission in the postmodern era.  I recommend it.

Abstract:

This dissertation analyses the development in the understanding of mission in the life and
writings of St Thérèse of Lisieux and considers its contemporary significance. The thesis
is that Thérèse progressed from a ‘mother missiology’ to a ‘sister missiology.’ This
missiological evolution is intrinsically united to Thérèse’s transcendence of the faith categories
of her era.

Initially, with her Catholic contemporaries, Thérèse regarded it as her duty to ‘mother’
unbelievers into divine life. This ‘mother missiology’ gradually became ‘sister
missiology’ as two movements of grace, namely the emergence of the ‘little way’ and
Thérèse’s intensifying union with Jesus, the kenotic Christ, took Thérèse beyond her
era’s vision of faith. The paradigm of ‘sister missiology’ has an entwined dual dynamic:
radical solidarity with unbelievers and radical receptivity to the gratuitous outpouring of
God’s love.

Sister missiology is demonstrated to be a potentially vital enabler of the Church’s
missionary agenda in the twenty-first century. It is able to facilitate the realisation of the
missionary objectives of the Second Vatican Council and offers a road-map for the
Church’s engagement with postmodernity.

Citation:  Jones, Michelle, "From Mother to Sister: The Development in the Understanding of Mission in the Life and Writings of St Thérèse of
Lisieux and its Contemporary Relevance" (2006). Theses. Paper 42.
http://researchonline.nd.edu.au/theses/42