Ambrose of Milan

Christ, detested by coiling snakes and beset by reptiles crawling on the earth, flees from the barren plain; he knows no dwelling except the heights of virtue; he knows no home except among those daughters of the church who can say, "We are a sweet fragrance of Christ to God." For some indeed, it is an odor of death, leading to death, for those who perish; but to others, it is an odor of life, leading to life—in those namely, who with living faith, breathe the fragrance of the Lord's resurrection.

Concerning Virginity 9:49 ↗

Bede

Flee, my beloved, etc. This phrase can rightly be understood both concerning the triumph of the Lord's ascension and concerning those things which occur daily in the Church. For the beloved flees after speaking to the bridegroom and his sister, because, having completed the dispensation of our Redemption, he returned to the heavens. …

Commentary on the Song of Songs ↗

Robert of Tombelaine

The beloved flees, because he hides himself from reprobate hearts so that he may not be understood by them. For when reprobate minds approach the hearing or reading of God's words with perverse intention, by a just judgment they do not find the truth which they do not seek with a worthy desire. Hence the very Wisdom of God says: "The wicked shall seek me and shall not find me" (John 7:34). …

Commentary on the Song of Songs, Chapter 8 ↗