…"spiritual ecumenism" was first used by the Abbe Paul Couturier from Lyon, France, in the mid-1930s, to describe an approach to ecumenism that was grounded in deeper conversion of all to Christ, was rooted in and nourished by prayer on the model of the prayer of Jesus in John 17, and was deeply penitent for the sins of all parties against the unity of the one body. Couturier's vision for ecumenism was adopted by the Catholic bishops at Vatican Two, and found clear expression in the decree on ecumenism. John Paul II strongly endorsed the teaching of the council on spiritual ecumenism in his encyclical letter Ut Unum Sint in 1995.
Source: Fr. Peter Hocken - Pentecost and Parousia, Peter Hocken - p. 91 / UR 6-8 / UUS 15-17, 21-27.