A witness saves lives when they tell the truth; when they tells lies, they betray people.
The eighth commandment forbids misrepresenting the truth in our relations with others. This moral prescription flows from the vocation of the holy people to bear witness to their God who is the truth and wills the truth. Offenses against the truth express by word or deed a refusal to commit oneself to moral uprightness: they are fundamental infidelities to God and, in this sense, they undermine the foundations of the covenant.
Before Pilate, Christ proclaims that He “has come into the world, to bear witness to the truth.” The Christian is not to be ashamed then of testifying to our Lord. In situations that require witness to the faith, the Christian must profess it without equivocation, after the example of Paul before his judges. We must keep “a clear conscience toward God and toward men.”
The duty of Christians to take part in the life of the Church impels them to act as witnesses of the Gospel and of the obligations that flow from it. This witness is a transmission of the faith in words and deeds. Witness is an act of justice that establishes the truth or makes it known.
Martyrdom is the supreme witness given to the truth of the faith: it means bearing witness even unto death. The martyr bears witness to Christ who died and rose, to whom he is united by charity. He bears witness to the truth of the faith and of Christian doctrine. He endures death through an act of fortitude.
The Church has painstakingly collected the records of those who persevered to the end in witnessing to their faith. These are the acts of the Martyrs. They form the archives of truth written in letters of blood.