Gregory the Great
Catena Aurea · Matthäusevangelium 2
When they saw the star, they rejoiced with exceeding great joy. And when they were come into the house, they saw the young Child with Mary His mother, and fell down, and worshipped Him: and when they had opened their treasures, they presented unto Him gifts; gold, and frankincense, and myrrh.
(ubi sup.) Something further may yet be meant here. Wisdom is typified by gold; as Solomon saith in the Proverbs, A treasure to be desired is in the mouth of the wise. (Prov. 21:20.) By frankincense, which is burnt before God, the power of prayer is intended, as in the Psalms, Let my speech come before thee as incense. (Ps. 141:2.) In myrrh is figured mortification of the flesh. To a king at his birth we offer gold, if we shine in his sight with the light of wisdom; we offer frankincense, if we have power before God by the sweet savour of our prayers; we offer myrrh, when we mortify by abstinence the lusts of the flesh.