"Deacons, likewise, are to be men worthy of respect, sincere, not indulging in much wine, and not pursuing dishonest gain. They must keep hold of the deep truths of the faith with a clear conscience. They must first be tested; and then if there is nothing against them, let them serve as deacons.

In the same way, their wives are to be women worthy of respect, not malicious talkers but temperate and trustworthy in everything.

A deacon must be the husband of but one wife and must manage his children and his household well. Those who have served well gain an excellent standing and great assurance in their faith in Christ Jesus."    - 1 Timothy 3:8-13

The Deacons are responsible for ministering to people in need, including the sick, the friendless, and people in distress.  They develop methods for collecting and distributing the gifts of the people and are stewards of the church property that the Lord provides.  The Deacons are under the authority of the Session. 

Twin Oaks Presbyterian Church Diaconate Mission Statement
The Deacons are the hands and feet of Christ to the church which they have been called to serve in love.  Their principal focus is to the ministry of mercy in Word and deed.  It is a ministry defined by the compassion and gospel of Christ, and empowered by the Holy Spirit.  With prayer, humble hearts, and wise counsel, Deacons must prioritize ministries and ascertain the urgency of the needs of mercy.  A Deacon served the body of Christ by assisting and supporting the worship of God, shepherding of the fold, managing and maintaining the gifts given in obedience and praise to God, ministering mercy in Word and deed, and leading the cogregation in deeds of mercy and service.

Sources:  
1.  The Book of Church Order, Presbyterian Church in America; Published by the Office of the Stated Clerk of the General Assembly of the Presbyterian Church in America; Copyright 2006
2.  Mission Statement:  Based on the Holy Bible, New International Version, Book of Church Order Chapter 9, Presbyterian Church in America Digest Position Papers: 1973 - 1993 "Biblical Guidelines For Mercy Ministry in the PCA".