Our understanding of what Jesus taught us continues to evolve, as new knowledge about biblical exegesis continues and as our knowledge of life and the universe grows.  That is why it has taken 2000 years to develop doctrine to where it is now and to discover that not everything Jesus was teaching us was understood all those centuries ago.  For example, Adam and Eve both had mothers and fathers, the sun does not circle the earth, slavery is evil, but charging interest on loaned money is not necessarily evil.  We also took quite some time figuring out what the seven sacraments are and what the priesthood is.  Perhaps there are more sacraments yet to be realized.  And, we should recognize that we are still working on that "priesthood" thing - maybe it is time to go back to the earlier thinking that priests could marry and adopt a new recognition that women can be priests and lead services, as they sometimes did in the earliest church.)  

Big mistake to think we always got it all right.