21 A decisive step in the difficult search for ways of putting this fundamental ecclesial principle into practice is illustrated in the choice of the seven, which marked the origin of the diaconal office (cf. Acts 6:5-6). In the early Church, in fact, with regard to the daily distribution to widows, a disparity had arisen between Hebrew speakers and Greek speakers. The Apostles, who had been entrusted primarily with “prayer” (the Eucharist and the liturgy) and the “ministry of the word”, felt over-burdened by “serving tables”, so they decided to reserve to themselves the principal duty and to designate for the other task, also necessary in the Church, a group of seven persons. Nor was this group to carry out a purely mechanical work of distribution: they were to be men “full of the Spirit and of wisdom” (cf. Acts 6:1-6). In other words, the social service which they were meant to provide was absolutely concrete, yet at the same time it was also a spiritual service; theirs was a truly spiritual office which carried out an essential responsibility of the Church, namely a well-ordered love of neighbour. With the formation of this group of seven, “ diaconia ”—the ministry of charity exercised in a communitarian, orderly way—became part of the fundamental structure of the Church.
Source: Deus Caritas Est (Vatican.va)