1 Now in these days when the disciples were increasing in number, a complaint by the Hellenists arose against the Hebrews because their widows were being neglected in the daily distribution. 2 And the twelve summoned the full number of the disciples and said, “It is not right that we should give up preaching the word of God to serve tables. 3 Therefore, brothers, pick out from among you seven men of good repute, full of the Spirit and of wisdom, whom we will appoint to this duty. 4 But we will devote ourselves to prayer and to the ministry of the word.” 5 And what they said pleased the whole gathering, and they chose Stephen, a man full of faith and of the Holy Spirit, and Philip, and Prochorus, and Nicanor, and Timon, and Parmenas, and Nicolaus, a proselyte of Antioch. 6 These they set before the apostles, and they prayed and laid their hands on them (Acts 6:1-6).
This is often though to document the origin of the deaconate. I suppose we could quibble over terminology, but that’s secondary.
What’s striking about this account is how the Apostles are making up church polity on the fly. There’s no preexisting office that deals with this contingency. So they simply create one on the spot to deal with the situation. It’s a pragmatic solution to a practical problem. . The Jerusalem church didn’t have the internal organization already in place to fix this problem, so the Apostles do what’s necessary to address the need. They don’t even consult with God beforehand. They adapted to the demands of the situation.
This is very different from the traditional Roman Catholic notion where God handed down a complete ecclesiological package.