4 And you were first anointed on the forehead, that you might be delivered from the shame, which the first man who transgressed bore about with him everywhere; and that with unveiled face ye might reflect as a mirror the glory of the Lord. Then on your ears; that you might receive the ears which are quick to hear the Divine Mysteries, of which Esaias said, The Lord gave me also an ear to hear; and the Lord Jesus in the Gospel, He that has ears to hear let him hear. Then on the nostrils; that receiving the sacred ointment ye may say, We are to God a sweet savour of Christ, in them that are saved. Afterwards on your breast; that having put on the breast-plate of righteousness, you may stand against the wiles of the devil. For as Christ after His Baptism, and the visitation of the Holy Ghost, went forth and vanquished the adversary, so likewise ye, after Holy Baptism and the Mystical Chrism, having put on the whole armour of the Holy Ghost, are to stand against the power of the adversary, and vanquish it, saying, I can do all things through Christ which strengthens me.
Source: Catechetical Lectures (New Advent)