Baptism is a gift from God that is waiting to be opened to be fully and joyfully experienced by each Christian, said the preacher of the papal household.

What awaits each person is the astonishment of faith, "that eyes-wide-open and that 'Oh!' what splendor in opening the gift," and coming to a full understanding that each person is a child of God and, therefore, all are brothers and sisters to each other, said Cardinal Raniero Cantalamessa Dec. 3.

The cardinal offered his first Advent reflection to officials of the Roman Curia in the Vatican's Paul VI hall, while Pope Francis was visiting Cyprus. The meditation looked at St. Paul's teaching in his letter to the Galatians on God sending his son so that people may become "God's free children in Christ."

Cardinal Cantalamessa said a "mortal danger" for Christians is when they do not fully open their eyes to the reality and wonder of being a child of God or when they take it for granted.

Jesus teaches that God is the father of every human being -- sinners and the just -- and that he loves and cares for each one individually, he said.

"It will be thanks to this one Son that humanity can become children of God, too, in a real sense and not just metaphorically," he said.

The grace of baptism confers many gifts: "divine filiation, remission of sins, the dwelling of the Holy Spirit (and) the theological virtues of faith, hope and charity embryonically infused in the soul," he said.

Through baptism, one is truly born from God, receiving "his Spirit that is, if you will, his DNA" so that "the life of God himself flows" within a person, he said.

But, it is one thing to know the truth of one's faith and another to actually believe and experience it, he said. People must go "from faith to wonderment. I would dare say, from faith to incredulity! A very special incredulity" in which a person of faith believes, but realizes it is so boundless, enormous and incredible.

Baptism, he said, "is like a jam-packed gift-parcel kept sealed ... like some Christmas gifts that were forgotten somewhere" and have not been opened yet.

A baptized person possesses all the titles or privileges for living a Christian life and receiving its fruits, "but does not possess the fullness of the reality," he said, citing St. Augustine's explanation of the difference between the sacrament itself and the effect or grace of the sacrament.

"So what is missing then? We are missing faith-astonishment, that eyes-wide-open" wonder in opening that gift -- an "illumination" that is baptism, he said.

No one can tell God he must choose a favorite among his children or insist he belongs on someone's side, he said. "You cannot dictate to a father this cruel alternative to choose between two children just because they are fighting with each other."

Cardinal Cantalamessa said, "When we are at odds with someone, before even asserting and arguing our point of view -- which is also legitimate and sometimes due -- we will say to God, 'Father, save my brother, save both of us. I don't want that I am right and he is wrong; I want that he is in the truth, too, or at least in good faith.'"

Being merciful like this toward others is indispensable for living life according to the Holy Spirit and for living with others, especially for families, communities and even the Roman Curia, he said.