Bede

A bundle of myrrh is my beloved to me, etc. And this, according to the letter, we read was fulfilled concerning our Savior when, after His passion was accomplished and His body taken down from the cross, Nicodemus came, bringing a mixture of myrrh and aloes, about a hundred pounds' weight. And they took His body and wrapped it in linen cloths with spices. …

Commentary on the Song of Songs ↗

Bernard of Clairvaux

1. "A bundle of myrrh is my beloved to me; he shall abide between my breasts" (Song 1:12). Before he was king, now he is beloved; before on the royal couch, now between the breasts of the bride. Great is the power of humility, to which even the majesty of the Godhead so easily inclines itself. Quickly the name of reverence was changed into the word of friendship: and he who was far off was in a short time made near. "A bundle of myrrh is my beloved to me." Myrrh, a bitter thing, signifies hard and harsh tribulations. …

Sermons on the Song of Songs, Sermon 43 ↗

Robert of Tombelaine

The bodies of the dead are customarily preserved with myrrh, lest they putrefy. Indeed, we apply myrrh to bodies lest they putrefy, when we restrain our members from the corruption of lust through their mortification after Christ's example; lest, if we leave them without seasoning, our bodies, dissolved by corruption, become food for eternal worms. …

Commentary on the Song of Songs, Chapter 1 ↗