As I researched the oils, I became fascinated with their role and use in Biblical times. Here's a bit of what I found out.
Gold of course is the tribute brought to a king. Essential oils were extremely precious and valuable in biblical times, equal to and more practical than gold, so bringing them to Mary was both practical and symbolic.
Symbolically, there is a verse in Exodus that has God telling Moses to craft a Holy Oil and Holy Incense from essential oils that were available ... both include Frankincense. So when the song mentions Frankincense, it's likely that what was brought was a blend of Holy Oil. And this oil of Frankincense was often used to annoint the newborn sons of kings. But Frankincense had a practial side as it was burned as incense, taken orally and applied to the skin.
On the practical side, Myrrh was the aspirin of biblical times with a spiritual spin. So, to bring Myrrh essential oil to a woman who had just given birth made great sense because it is a very healing oil and Mary would have known precisely how to use it. Myrrh is an antiseptic and she would have used it on the baby's new belly button and also good for healing coughs, colds and little cuts and bruises all boys seem to attract. She would have also known that Myrrh is good for stretch marks. She would have also known that myrrh promotes spiritual awareness and is emotionally uplifting. When rubbed on her body as a breast-feeding mother, it would communicate a sense of security and well being to both her and the child.
But if you read the lyrics (below) Myrrh also has a connotation of doom to it that comes from it's use in preserving and preparing bodies for burial. So many scholars feel this gift was also a prophecy of what was to come for the baby.
Why is none of this laid out or referred to in the Bible? That's the most interesting part to me ... because everyone knew it, these things were common knowledge of the day, and the Bible's writers could not imagine that 2,000 years later we westerners would have so little knowledge of and experience with healing oils.
We three kings of Orient are
Bearing gifts we traverse afar
Field and fountain, moor and mountain
Following yonder star
O Star of wonder, star of night
Star with royal beauty bright
Westward leading, still proceeding
Guide us to thy Perfect Light
Born a King on Bethlehem's plain
Gold I bring to crown Him again
King forever, ceasing never
Over us all to rein
O Star of wonder, star of night
Star with royal beauty bright
Westward leading, still proceeding
Guide us to Thy perfect light
Frankincense to offer have I
Incense owns a Deity nigh
Pray'r and praising, all men raising
Worship Him, God most high
O Star of wonder, star of night
Star with royal beauty bright
Westward leading, still proceeding
Guide us to Thy perfect light
Myrrh is mine, its bitter perfume
Breathes of life of gathering gloom
Sorrowing, sighing, bleeding, dying
Sealed in the stone-cold tomb
O Star of wonder, star of night
Star with royal beauty bright
Westward leading, still proceeding
Guide us to Thy perfect light
Glorious now behold Him arise
King and God and Sacrifice
Alleluia, Alleluia
Earth to heav'n replies
O Star of wonder, star of night
Star with royal beauty bright
Westward leading, still proceeding
Guide us to Thy perfect light