Let us now return to the exposition of the Gospel, where we previously left it. The astronomers went into the place where the child was staying, and found him with his mother. Then with prostrate bodies they worshipped Christ, and opened their coffers, and offered to him threefold gifts, gold, and incense, and myrrh. Gold is fitting for a king; incense belongs to God’s service; with myrrh the bodies of the dead are prepared that they may not soon rot. These three astronomers worshipped Christ, and offered to him symbolic gifts. The gold betokened that he is true King; the incense that he is true God; the myrrh that he was then mortal, though now he continues immortal in eternity…
My brothers, let us offer to our Lord gold, for we confess that he is true King, and rules everywhere. Let us offer to him incense, for we believe that he was always God, who at that time appeared as a man. Let us bring him myrrh, for we believe that he was mortal in our flesh, who is incapable of suffering in his divine nature. He was mortal in human nature before his Passion, but he is henceforth immortal, as we all shall be after the universal resurrection.
We have spoken of these threefold gifts, how they apply to Christ. We also wish to say how they apply to us in a figurative sense. Truly gold betokens wisdom; as Solomon said, “A goldhoard much to be desired lies in the mouth of a wise man.” Incense represents holy prayer, of which the psalmist sang, “Lord, let my prayer be sent forth like burning incense in thy sight.” By myrrh is shown the mortality of our flesh, of which Holy Church says, “My hands dropped myrrh.” To the born King we bring gold, if we are shining in his sight with the brightness of heavenly wisdom. Incense we bring him, if we set fire to our thoughts on the altar of our heart with the eagerness of holy prayers, so that through heavenly desire we may give forth something of a sweet smell. Myrrh we offer him if we quell the lusts of the flesh by self-restraint.
Read it all (and note the link to the full sermon text).