sometimes the simple ones get me, can you help ?
That’s an excellent question that has a simple, if puzzling, answer. The name comes from the Latin word missa. ” In Latin the Mass ended with Ite missa est which translated into English means “Go, it is sent,” the “it” being the Church. The Mass gets its name from the liturgical dismissal at its conclusion. *Missa *was spoken at the end of the liturgy of the word (dismissal of catechumens) and at the end of Mass (dismissal after the Eucharist). According to the Catholic Encyclopedia it was some time after Gregory the Great (d. 604) that the word was applied to the entire liturgy.
While there may be simple cultural reasons why this took place, there is an interesting theology to be gleamed from the entire liturgy taking its name from the dismissal. Afterall, the Great Commission was to go out to all the world and preach the Gospel. As Christians we are called to gather and worship but also to go out and proclaim the Gospel through our lives. It is not an either/or but a both/and situation.