This Buddhist temple established during the early Unified Silla period (676-935) inside a cave naturally formed on the rocky cliff of Palgongsan Mountain in Gunwi-gun, Gyeongsangbuk-do is regarded historically important largely because it appeared before the internationally renowned Seokguram Grotto (National Treasure No. 24). The cave temple is enshrining a stone Buddhist triad known to have been made in about 700. The principal Buddha of the triad is seated cross-legged position on a cuboid pedestal, featuring a disproportionately large head with usnisa (a protuberance symbolizing supreme wisdom) and face wearing a stern look unlike other Buddha statues made in the same period which typically wear benign, friendly smile. The Buddha is in a veil robe revealing the curves of the body and is draped further down to cover the knees and feet and then the pedestal. The symbolic hand gesture, where the right hand is placed on the right knee with fingers downward, shows that he is interested in expelling evil. The two bodhisattvas standing on both sides of the Buddha display the same appearance in which each wears a crown carved with a miniature Buddha at the front center and holds a kundika, ritual water sprinkler, in one hand. They are also marked by wearing the beaded neck ornament, armlet, and robe draped downward, creating long U-shaped folds over the waist and knees. The comparatively slender and proportionate body with clearly defined neck, waist and legs shows an influence from the style developed in Tang (618-907), the Chinese dynasty of the same period. The triad is regarded historically significant in that it provides a fine example to show the transition of early Korean Buddhist sculpture from the Three Kingdoms to the following Unified Silla Periods and that it is enshrined at one of the first natural caves which was turned into a full-fledged temple in Korea.