Two Puzzles about Baptism from 3 Nephi 11
The Nephites baptized before Christ. At the time of 3 Nephi 11, they would have been practicing baptism in a tradition and with authority that traced back at least to Alma.
Yet Christ gave Nephi and the other disciples authority to baptize.
And the Lord said unto him: I give unto you power that ye shall baptize this people when I am again ascended into heaven.
And again the Lord called others, and said unto them likewise; and he gave unto them power to baptize.
Christ gives them the sacrament which is usually something that would only be done for the already baptized. Why did Christ renew the grant of authority and require rebaptism?

