have not given due importance to the relationship between the Church as communion and the Church as sacrament. 2. Bearing in mind the doctrinal, pastoral and ecumenical importance of the different aspects regarding the Church understood as Communion, the Congregation for the Doctrine of the Faith has considered it opportune, by means of this Letter, to recall briefly and to clarify, where necessary, some of the fundamental elements that are to be considered already settled also by those who undertake