[Latin for “mother”] Mater is the mater-ialization of the God Flame, the means whereby Spirit acquires, ‘physically’, fourfold dimension and form through the feminine, or negative, polarity of the Godhead. The term used interchangeably with “Matter” to describe the planes of being that conform to and comprise the universal chalice, or matrix, for the descent of that Light of God which is perceived as Mother.
It is through this Mother aspect of himself that the Spirit of God, the Father, evolves the consciousness of the Christ, the only begotten Son of God, in his children as a developing Christ-Self awareness through the threefold flame—divine spark and signet of their joint-heirship to be.
The soul that descends from the plane of Spirit abides in time and space in Mater for the purpose of its spiritual/physical evolution that necessitates self-mastery of the energies of God through the judicious exercise of free will.
The four lower bodies of man, of a planet, and of systems of worlds—as the four planes, quadrants and cosmic forces—occupy and make up the frequencies of Matter.
Mark L. Prophet and Elizabeth Clare Prophet, Saint Germain On Alchemy: Formulas for Self-Transformation.