Over at his blog, Gerard Nadal makes a compelling argument that it started at the Last Supper:
As Holy Week looms large on the horizon, I’m thinking out loud a question I have thought to myself for years:
Were the Apostles really the first Deacons in the Church? Did the Apostles institute the Diaconate, or did Jesus at the Last Supper?
I believe that a scriptural case may be made for the Apostles being the first deacons. To begin, we all know that the Last Supper was the moment where Jesus instituted His Priesthood, conforming His apostles to himself as Priest when He commanded them:
“Whenever you do this, do this in remembrance of me.”
In that moment, with that command, Jesus conformed His Apostles to Himself as Priest. The Church teaches that at the moment of ordination to the priesthood, the very nature of the man is changed forever. A priest is a priest forever.
We are also taught, in Acts, that the Apostles selected and ordained the first deacons, conforming them to Christ the Servant…
…The Church also teaches that when a man is ordained to the diaconate he undergoes a change in his very nature, that he is a deacon forever. He is conformed to Christ the Servant, and theirs is a ministry of service. (It is important to note that every priest remains a deacon, forever.)
“If I, therefore, the master and teacher, have washed your feet, you ought to wash one another’s feet. I have given you a model to follow, so that as I have done for you, you should also do.”
With those words, Jesus conformed His apostles to Himself as servants, and this before He instituted the Eucharist. Going ahead to the dilemma of the Apostles in Acts, we see them exercising their ministry of service until the growth of the Church placed too many demands on them. When they laid hands on the seven they were transmitting what had been given to them at the Last Supper, namely, the ministry of service.
There’s much more. Read it all.