D&C 22

 The Lord reasoned with those that thought their previous baptisms were still in affect - 

"Behold, I say unto you that all old covenants have I caused to be done away in this thing; and this is a new and an everlasting covenant, even that which was from the beginning."  (Doctrine and Covenants 22:1)

All covenants, including the law of Moses, availeth nothing in the eternal scheme of things except unless they are made according to the authority and doctrine of the new and everlasting covenant.