The Church’s teaching and prayer throw light on how we should defend the act of faith and how we shouldn’t.

Time and again, she insists that faith in God must be freely professed. This doctrine is stated in the Catechism, the Canon Law, and the Declaration on Religious Liberty. The world is invited to faith and conversion but not coerced.

During the Mass of Friday of the Passion of the Lord, the Church prays for those who do not believe in Christ:

Almighty ever-living God, grant to those who do not confess Christ that, by walking before you with a sincere heart, they may find the truth and that we ourselves, being constant in mutual love and striving to understand more fully the mystery of your life, may be made more perfect witnesses to your love in the world. Through Christ our Lord.

Following that, she prays for those who do not believe in God:

Almighty ever-living God, who created all people to seek you always by desiring you and, by finding you, come to rest, grant, we pray, that, despite every harmful obstacle, all may recognize the signs of your fatherly love and the witness of the good works done by those who believe in you, and so in gladness confess you, the one true God and Father of our human race. Through Christ our Lord.

The first prayer wants believers to be “more perfect witnesses to [Christ’s] love in the world.” The second wants believers to help unbelievers to recognize God through “the witness of [their] good works.”

Our charity in action, therefore, is both a witness to God’s love and a defense of our belief in God. “Charity in action” means responding to God’s call to reproduce the image of Jesus, choosing to be eternally happy with God, being truly free, acting morally, having moral feelings, having a moral conscience, being virtuous, and avoiding and seeking mercy for sin. 

St. Francis Xavier, the great Jesuit missionary, perfectly demonstrated all of that. 

He converted, baptized, and preached in northern and southern India and Japan. He celebrated the sacraments and translated the great prayers into the local languages. He was the Church’s greatest evangelist since Saints Peter and Paul died. 

He was also a Spaniard who didn’t speak Asian languages and drew the suspicions and hostilities of those who practiced the local religions and superstitions. 

None of his missionary work would have happened without his grace-powered life of perfect charity in action. He and all the saints are the best defense of our belief in God, which is the fundamental act of faith.