Original sentence: As a lead to the Memorial Acclamation, the priest says or sings: "The mystery of faith".The phrase mysterium fidei had previously been included in the formula of consecration of the wine spoken  inaudibly by the priest, appearing as follows (here accompanied by an unofficial English translation):.This introductory phrase, mysterium fidei in the Latin original, was previously translated loosely into English as "Let us proclaim the mystery of faith", and in some places was sung or spoken by the deacon instead of the priest in spite of the clear instruction in the Missal itself and in the apostolic constitution Missale Romanum with which Pope Paul VI promulgated the revision of the Roman Missal
Edited sentence: As a lead to the Memorial Acclamation, the priest says: "The mystery of faith".The phrase mysterium fidei had previously been included in the formula of consecration of the wine spoken inaudibly by the priest, appearing as follows (here accompanied by an unofficial English translation):.This introductory phrase, mysterium fidei in the Latin original, was misleadingly translated into English as "Let us proclaim the mystery of faith", and in some places was sung or spoken by the deacon instead of the priest in spite of the clear instruction in the Missal itself and in the apostolic constitution Missale Romanum with which Pope Paul VI promulgated the revision of the Roman Missal