Bede

King Solomon made himself a palanquin, etc. It is called a palanquin because it carries the bodies of those seated or reclining at a banquet, or because it is usually carried from place to place according to the opportunity of the times. The holy Church is rightly compared to this, as it lifts believers to the feast of eternal happiness and is carried throughout the entire world by the ministry of its preachers. …

Commentary on the Song of Songs ↗

Bonaventure

And he said: I have wanted to lead you to this "tree of life." "King Solomon hath made him a litter of the wood of Libanus. The pillars thereof he made of silver, the seat of gold, the going up of purple: the midst he covered with charity." The seat of gold is contemplative wisdom. And this no one has, except one who has the pillars of silver, which are the virtues buttressing the soul. The going up of purple is charity which makes [the soul] go up to the higher things and down to the lower.

Collations on the Hexaemeron, Collation 23 ↗

Robert of Tombelaine

The timbers of Lebanon are declared to be imperishable. Therefore King Solomon made himself a litter from the timbers of Lebanon, because, according to the grace of His foreknowledge, Christ built the holy Church from saints who would endure forever.

Commentary on the Song of Songs, Chapter 3 ↗