If faith, as I was taught, is the acceptance of a truth on the authority of God revealing it, why does Christ speak of faith that can move mountains? This is not the same as accepting a truth. Is there another kind of faith?
Yes, there is. While we customarily define faith in the way you did at the beginning of your question, there is another meaning of the word, which is equally biblical, completely acceptable and indeed necessary.
This second kind of faith, sometimes called fiducial faith, from the word for trust or confidence, is mentioned numerous times in the scriptures.
For example, it was his complete trust, or faith, in God that led Abraham to leave his home country and set off for an unknown land (cf. Gen 12:1-8; Heb 11:8), and that moved his wife Sarah to believe that she could bear a child when she was past the age of child bearing (cf. Gen 18:11-14; Heb 11:11).
In the New Testament, when Our Lady was told that she would conceive a son by the power of the Holy Spirit while remaining a virgin, she immediately believed and accepted:
“Behold, I am the handmaid of the Lord; let it be to me according to your word” (Lk 1:38). Although Mary did not ask for a sign, the angel Gabriel gave her one: her elderly kinswoman Elizabeth was in her sixth month with child, “For with God nothing will be impossible” (Lk 1:37).
This assurance from the angel is the basis for our trust that God can do the impossible.
The Catechism of the Catholic Church calls this unquestioning response to the word of God “the obedience of faith”:
“To obey (from the Latin ob-audire, to ‘hear or listen to’) in faith is to submit freely to the word that has been heard, because its truth is guaranteed by God, who is Truth itself. Abraham is the model of such obedience offered us by Sacred Scripture. The Virgin Mary is its most perfect embodiment” (CCC 143, 144).
Saint Cyril of Jerusalem, in his catechesis in the fourth century, comments:
“The one word faith can have two meanings. One kind of faith concerns doctrines. It involves the soul’s assent to and acceptance of some particular matter… The other kind of faith is given by Christ by means of a special grace… Now this kind of faith, given by the Spirit as a special favour, is not confined to doctrinal matters, for it produces effects beyond any human capability. If a man who has this faith says to this mountain move from here to there, it will move. For when anybody says this in faith, believing it will happen and having no doubt in his heart, he then receives that grace” (Cat. 5, De fide et symbolo, 10-11).
It is of this second kind of faith, fiducial faith, that Christ speaks when he says: “Have faith in God. Truly, I say to you, whoever says to this mountain, ‘Be taken up and cast into the sea,’ and does not doubt in his heart, but believes that what he says will come to pass, it will be done for him. Therefore I tell you, whatever you ask in prayer, believe that you receive it, and you will” (Mk 11:22-24).
In this Year of Faith we do well to examine ourselves on how strong our faith is.
Do we really believe that if we pray with faith our son or daughter will return to the practice of the faith, a sick person will get better, a troubled marriage will stay together, someone out of work will find a job, a single person will find a suitable spouse?
If we feel that our faith is weak, like the apostles we can ask our Lord: “Increase our faith!” (Lk 17:5).
A good way to live this special year is to pray more often and with more confidence for difficult intentions. God does not always answer our prayers in the way we want, but he always hears them and he answers them in the way that is best.
And often he does grant what we are asking, showing us that “with God nothing will be impossible.”
The many miracles approved by the Vatican for causes of beatification and canonisation are proof that God can do the humanly impossible and that there were people praying with faith for those “impossible” intentions.
We should be among them. After all, Jesus assures us, “All things are possible to him who believes” (Mk 9:23).
So often, when we have tended to doubt God’s power or his willingness to help us, we have seen our prayers answered and he has had to say to us, as to St Peter, “O you of little faith, why did you doubt?” (Mt 14:31).