"It is the hour when the Word is found and the Cubic Stone is changed into the Mystic Rose.” - Scottish Rite's 18th Degree ritual for the Knight Rose Croix
The soul's journey of the "cubic stone" (earthly body or unrefined soul) as it evolves into the "mystic rose" (divine love, wisdom, and unity).
The rose symbolizes spiritual unfolding, beauty amid thorns (trials), and divine mystery.
In Rosicrucianism, it's the "Rosa Mundi" (Rose of the World)—enlightenment blooming from the cross of suffering.
The foundation of the Temple is built so that that the holy of holies may be enshrined, so that the shekinah may descend onto the Altar, so that the Holy Spirit may descend as the dove into the chalice of the Grail. There the Rose blooms
In the the Scottish Rite's 18th Degree ritual for the Knight Rose Croix, it's stated: "It is the hour when the Word is found and the Cubic Stone is changed into the Mystic Rose.”