If It So Be That They Are Built upon My Gospel

Speaking with his disciples in the temple, Christ tells them that they are built on his gospel.  This is the only appearance of this phrase in ancient scripture, and it's surprising.  In a temple context, what we expect to hear is that the worship is or should be built upon the rock.  Interestingly, these concepts are bridged in the Doctrine & Covenants, where we learn that the gospel is the rock.  This is coherent: the rock is the revelation, the look behind the veil and the place of meeting with its great occupant, the true good news.