4:5. Thy two breasts like two young roes that are twins, which feed among the lilies.
Thy two breasts, etc... Mystically to be understood: the love of God and the love of our neighbour, which are so united as twins which feed among the lilies: that is, the love of God and our neighbour, feeds on the divine mysteries and the holy sacraments, left by Christ to his spouse to feed and nourish her children.
4:6. Till the day break, and the shadows retire, I will go to the mountain of myrrh, and to the hill of frankincense.
4:7. Thou art all fair, O my love, and there is not a spot in thee.
4:8. Come from Libanus, my spouse, come from Libanus, come: thou shalt be crowned from the top of Amana, from the top of Sanir and Hermon, from the dens of the lions, from the mountains of the leopards.
4:9. Thou hast wounded my heart, my sister, my spouse, thou hast wounded my heart with one of thy eyes, and with one hair of thy neck.
4:10. How beautiful are thy breasts, my sister, my spouse! thy breasts are more beautiful than wine, and the sweet smell of thy ointments above all aromatical spices.
4:11. Thy lips, my spouse, are as a dropping honeycomb, honey and milk are under thy tongue; and the smell of thy garments, as the smell of frankincense.
4:12. My sister, my spouse, is a garden enclosed, a garden enclosed, a fountain sealed up.
My sister, etc., a garden enclosed... Figuratively the church is enclosed, containing only the faithful. A fountain sealed up... That none can drink of its waters, that is, the graces and spiritual benefits of the holy sacraments, but those who are within its walls.