The greek work diakonos simply means minister or servant, or even messenger, and is found mostly in the New Testament. We hear of the angels who minister to Jesus in the desert in Mark's Gospel (1:13). Martha is also an example of service for deacons (Luke 10:38). St. Paul mentions deacons at the start of his letter to the Philippians (1:1), and we also find in the Letter to Timothy the kind of qualities a deacon should have: “serious, not double-toungued, not addicted to much wine, not greedy for gain; they must hold the mystery of faith with a clear conscience.” (1 Tim 3:8) He then goes to on to say that they must be tested, and must be the husband of one wife and good administrators of their household.
The first deacons in the history of the Church are found in the Book of the Acts of the Apostles. Stephen was appointed to be the first, followed by six others (Acts 6:1-7) and they were called take up some of the labour in order to let the Apostles focus on being ministers of the Word. This special service was conferred on them by the laying on of hands and the prayers.
The deacons were put in charge of stewarding church funds and collecting alms for the widows and orphans; they also attended the needs of the poor. A great example of this is, of course, seen in the example of St. Lawrence who, when asked by the Roman emperor to deliver the church funds to him, he came back with all the poor and said, “these are the riches of the church!” A deacon then is someone who is on the ground, or 'dusty' as the etymology of the word deacon suggests, or someone who smells like the sheep as Pope Francis would say. If the bishop acts as the head of the body, then the deacons are the feet – running around getting dusty! He has a direct link to the bishop and is his messenger. He carries out the will of the bishop and takes on some of his more secular duties. In his letter to the Magnesians, St. Ignatius of Antioch commented on the good example of his fellow servant, deacon Zotion who was as attentive to his bishop as to the grace of God. They are to reflect the obedience of Jesus to the Father. This attentiveness to the Holy Spirit is also seen in the example of Philip (one of the appointed seven, not the apostle!) who is prompted to go and talk to the Ethiopian eunuch, so “he ran to him” (Acts 8:30) and explains the Scriptures to him and then baptizes him. After they both came out of the water, Philip had already been taken away by the Spirit and went to preach the gospel in all the surrounding towns. No rest for the deacons.
Not only does he run but he also serves solemnly at the Table of the Lord. As he is to be “entrusted with the service of Jesus Christ,” to use St. Ignatius of Antioch's words, he also has a special place in the liturgy and has a connection in particular with the sacred vessels. This is clearly seen in the Old Testament where the sons of Levi were chosen by God to “keep charge of the tabernacle of the covenant and all its furnishings and over all that belongs to it; they are to carry the tabernacle and all its furnishings, and they shall tend it, and shall encamp around the tabernacle (Num 1:50).” The deacons of the early church were appointed to present the gifts of bread and wine and prepare the altar. He would also administer the chalice and purify the vessels. It is here at the altar where the deacon learns how to serve.
They also had other functions which have been, for the most part, delegated to other members of the church. The deacon had to be able to sing because he would normally chant the psalm. What remains of the deacon's chanting today is the highest prayer of the year, the Exsultet which is sung at the Easter Vigil. He also used to keep order in church, acting like the modern-day pass-keeper.
The diaconate as we know it today is for the most part what it was like in the beginning. Some minor duties such as chanting and keeping order in church have been delegated to laymen. The essential elements are still there. He is to be dusty with running, proclaiming the Gospel, serving the poor and assisting at the Altar of the Lord. The deacon is called to imitate his Master who came not to be served, but to serve. (Mt 20:28)