The Ethiopian Evangelical Church Mekane Yesus (EECMY), the largest Lutheran church globally, serves as a case for analysing liturgical practices. This paper examines the relationship between volunteer involvement in liturgy and congregational dynamics by inquiring how the participation of lay people and the liturgical inclusion of children shape ecclesial identity and congregational growth. Drawing on qualitative interviews with pastors and laity and participant observation of five Sunday services, the study investigates how this involvement is facilitated through liturgical adaptation to cultural and charismatic expressions, volunteerism in organising Sunday services, and strategies for recruitment and training. A specific focus of the analysis is the role of children in the liturgy. The structure of the service prior to the children's departure for Sunday school provides a window into how clergy and laypeople pray for them, and how children participate through their own prayer, recitation of scripture, and singing. This inclusion, which positions children as participants alongside adults, is explored as a mechanism for establishing belonging. In a context where ordained clergy are scarce for a church of 12 million members, reliance on volunteer ministry serves not merely as a logistical necessity, but as a theologically founded praxis. Applying the lenses of liturgical studies and missiology to the model of "participatory liturgy", the study examines how the formation of ecclesial identity and contextual adaptations sustain the vitality of non-Western ecclesial structures.