The Greek verb leitourgeo means to render public service, to minister, to perform sacred/priestly duties. In secular Greek it referred to performing public duties at one's own expense. In the NT it takes on priestly and sacrificial dimensions.
Leitourgeo is the verb that gives us 'liturgy' — but its biblical meaning is far richer than formal religious procedure. In Romans 15:27, Paul uses it for the Gentiles' material support of Jewish believers — an act of worship by serving. Hebrews 10:11 contrasts the daily leitourgon of Levitical priests (offering sacrifices that could not take away sin) with Christ's once-for-all sacrifice. The climactic NT use is Acts 13:2: 'While they were worshiping (leitourgounton) the Lord and fasting, the Holy Spirit said, “Set apart for me Barnabas and Saul for the work to which I have called them.” Mission flows from worship; the sending of the first missionaries was embedded in an act of leitourgia. True liturgy — true service to God — always issues in mission.