Is the LDS Temple concept of ancient origin?
Again, here is my short answer, followed by more detail below: The revealed LDS (Mormon) Temple concept restores many elements from ancient worship, including early Christian baptism for the dead, ancient patterns of covenant making, etc., and Christian worship in the Temple. Though revealed in modern times, the LDS Temple is a restoration of several things that God had previously revealed in earlier ages.
Again, here is my short answer, followed by more detail below: The revealed LDS (Mormon) Temple concept restores many elements from ancient worship, including early Christian baptism for the dead, ancient patterns of covenant making, early Christian initiation rituals or “mysteries” (see Masonry and the LDS Temple with sections by W. John Walsh, Kenneth W. Godfrey, nnd Michael T. Griffith), and Christian worship in the Temple. Though revealed in modern times, the LDS Temple is a restoration of several things that God had previously revealed in earlier ages.