All believers, living and dead are a part of the Communion of Saints. The Catechism says, "We believe in the communion of all the faithful of Christ, those who are pilgrims on earth, the dead who are being purified, and the blessed in heaven, all together forming one Church; and we believe that in this communion, the merciful love of God and his saints is always [attentive] to our prayers" (CCC 962).
The saints are exemplars of how to follow Christ; they teach us how to live faithful and holy lives. The saints are our advocates and intercessors, and they are also friends and mentors.
The Saints in Scripture
In scripture, Paul addresses many of his letters to the various local communities under the title of “saints:” Romans, 1 and 2 Corinthians, Ephesians, etc. The term “saints” was also applied to those whom Christians served. In 1 Corinthians we read that Paul made a collection in Corinth for the relief of the saints in Jerusalem.
Paul also talks about the Communion of Saints in that each of us participates by baptism in the one Body of Christ. In his letter to the Romans, Paul tells us “For as in one body we have many parts, and all the parts do not have the same function, so we, though many, are one body in Christ and individually parts of one another. Since we have gifts that differ according to the grace given to us” (Romans 12:4-6).
Paul is very clear that members of this common body had obligations to build up the community – these members were called “saints.” This is connected with the Jewish idea of being a holy nation, a covenanted people. The “saints” are those who have inherited the covenant.
As Christianity developed, the word saint came to be used more commonly to designate specific individuals who were held to be exemplars of the faith, and who were commemorated or venerated as inspirations to other Christians.
In the beginning of our Church’s history, many witnessed to their faith by giving their lives. Many of the followers of Christ were martyred rather horrendously. Some early saints were stoned, as was Stephen. In the Acts of the Apostles we read: “They threw him out of the city, and began to stone him….As they were stoning Stephen, he called out, ‘Lord Jesus, receive my spirit.’ Then he feel to his knees and cried out in a loud voice, ‘Lord, do not hold this sin against them;’ and when he said this, he fell asleep” (Acts 7:58-60).
Tradition has it that Peter chose to be crucified upside down and that St. Paul was beheaded. Ignatius of Antioch, was "ground like wheat" by the teeth of animals. Perpetua and Felicity, two young women, had to wait until after Felicity's baby was born before they could face the lions. During this time Perpetua wrote down her thoughts, giving us a firsthand account of martyrdom.
Tertullian rightly said that the blood of the martyrs was the seed of the Church.
Since the 10th century, the Church has officially applied the standard of holiness of life to certain individuals who lived exemplary Christian lives and through a lengthy process of prayer and study have declared that the individual is in heaven. Contrary to the belief of some, the Church does not "create" saints, but simply applies the standard of gospel holiness to those God permits the Church to know are in heaven. Canonization is a process that includes the calling forth of witnesses, verification of miracles and other holy actions and much research and scrutiny.