you did not believe him;
but tax collectors and prostitutes did.
Yet even when you saw that, you did not later change your minds and believe him.
What moves us to believe is not the fact that revealed truths appear as true and intelligible in the light of our natural reason: we believe "because of the authority of God himself who reveals them, who can neither deceive nor be deceived". So "that the submission of our faith might nevertheless be in accordance with reason, God willed that external proofs of his Revelation should be joined to the internal helps of the Holy Spirit." Thus the miracles of Christ and the saints, prophecies, the Church's growth and holiness, and her fruitfulness and stability "are the most certain signs of divine Revelation, adapted to the intelligence of all"; they are "motives of credibility" (motiva credibilitatis), which show that the assent of faith is "by no means a blind impulse of the mind".
-- CCC 156