Like Adest sponsus, this is a conductus, or processional song; the treble voices declaim the text - which is concerned with some of the same images that evoked in the reading that follows - in an early form of three-part harmony.
Gideon's courtyard is wet with dew from heaven; the bush, with fiery flame radiates without heat. The fruit and seed come forth from the shell; as a golden light! Grain comes forth from the chaff, the olive from the olive tree, the rock is made liquid from liquid.