The Roman Church does not use it. There is a strong theological tradition in the church stemming from St. Augustine that redefines the one-ness of God by asserting that God only loves God. This position has been made very popular in our time by Karl Barth, whose doctrine of God is more modalistic than Trinitarian. In terms of the church's own experience of becoming one, the parallel is to the church loving only itself and then loving only one's own subgroup within the church.
Congregations can easily define their task as serving themselves and their members.
Become a member. This love is the power to give people a life that they did not have before, the life of the children of God. This does not constitute returning to the womb and undoing the failure of conception and birth, but rather in receiving a life that is nourished by the love of God. Like Nicodemus' fascination with the womb, our world is fascinated with looking back to the beginning of the cosmos. Science is doing wonderful things.