Service (leitourgias). Old word from leōs (people, laos), leitos like dēmosios, public, and ergon, work. So public service either in worship to God (Luk 1:23) or benefaction to others (2Co 9:12; Phi 2:30). Our word liturgy is this word.
Filleth up (estin prosanaplērousa). Present active periphrastic indicative of double compound verb prosanaplēroō, Koiné[28928]š word, here and 2Co 11:9 only in N.T., to fill up by adding to. The Corinthians simply added to the total from others.
Unto God (tōi theōi). Dative case and with a certain suddenness as at close of 2Co 11:11, really a parenthesis between in the somewhat tangled sentence.