CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 2470–2473

2470 The disciple of Christ consents to "live in the truth," that is, in the simplicity of a life in conformity with the Lord's example, abiding in his truth. "If we say we have fellowship with him while we walk in darkness, we lie and do not live according to the truth."
2471 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 St. Paul before his judges. We must keep "a clear conscience toward God and toward men."
2472 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.

All Christians by the example of their lives and the witness of their word, wherever they live, have an obligation to manifest the new man which they have put on in Baptism and to reveal the power of the Holy Spirit by whom they were strengthened at Confirmation.

2473 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. "Let me become the food of the beasts, through whom it will be given me to reach God."