A letter from a pastor to the congregation WordNet 3.0 & Open English WordNet

A pastoral letter, often simply called a pastoral, is an open letter addressed by a bishop to the clergy or laity of a diocese or to both, containing general admonition, instruction or consolation, or directions for behaviour in particular circumstances. Wikipedia

A letter of a pastor to his charge; specifically, a letter addressed by a bishop to his diocese. Wiktionary

Letter of a pastor. Wiktionary (translation)

A communication from a bishop to the clergy of laity containing instructions, directions etc. Wiktionary