Pope Francis issued this apostolic letter, Desiderio desideravi, calling for "the rediscovery of a theological understanding of the liturgy and its importance in the life of the Church." In the new document, released on the feast of Sts. Peter and Paul, the Pope calls for unity in the Church, saying that this unity in turn requires the acceptance of changes mandated by Vatican II. "Let us abandon our polemics and listen together to what the Spirit is saying to the Church," he writes. "Let us safeguard our communion." The apostolic letter, consisting of 65 paragraphs and about 11,000 words, calls for "a serious and vital liturgical formation" for all Catholics. The Pope opens with a series of theological reflections on the fundamental importance of the Eucharistic liturgy, then goes on to laud the directives of Vatican II as a means of invigorating the spiritual life of the Church.