Nephi had already previewed the ministry of John the Baptist, the prophet who would prepare the way before the Lamb of God (1 Nephi 10:7–10).
The need for everyone to be baptized is shown in the reasons why Jesus was baptized:
1. “To fulfil all righteousness”; compare Matthew 3:15: Jesus himself fulfilled all requirements for celestial glory. 90
2. “He humbleth himself before the Father” (compare John 6:38; 8:28–29).
3. He “witnesseth unto the Father that he would be obedient unto him in keeping his commandments” (compare John 14:31; 15:9–10).
4. He “showeth unto the children of men the straitness of the path, and the narrowness of the gate, by which they should enter” (compare Matthew 7:13–14).
5. He “set the example before them” (compare John 13:15). The Savior can then say, “I am the way” (John 14:6); “Follow thou me” (compare John 21:22). And again, “Follow me, and do the things which ye have seen me do” (see also 3 Nephi 27:21). In other words, be baptized and obey all the other commandments, too.