Pistis Sophia 

IT came to pass, when Jesus had risen from the dead, that he passed eleven years discoursing with his disciples, and instructing them only up to the regions of the First Commandment and up to the regions of the First Mystery, that within the Veil, within the First Commandment, which is the four-and-twentieth mystery without and below--those [four-and-twenty] which are in the second space of the First Mystery which is before all mysteries,--the Father in the form of a dove.