36 Yet He tries the soul. He casts not His pearls before swine; if you play the hypocrite, though men baptize you now, the Holy Spirit will not baptize you. But if you approach with faith, though men minister in what is seen, the Holy Ghost bestows that which is unseen. You are coming to a great trial, to a great muster, in that one hour, which if you throw away, your disaster is irretrievable; but if you be counted worthy of the grace, your soul will be enlightened, you will receive a power which you had not, you will receive weapons terrible to the evil spirits; and if you cast not away your arms, but keep the Seal upon your soul, no evil spirit will approach you; for he will be cowed; for verily by the Spirit of God are the evil spirits cast out.
Source: Catechetical Lectures (New Advent)