Mormon concept - not biblical.
Are ordinances such as baptism not necessary?
No. The thief on the cross wasn't able to be baptized, yet Jesus promised him salvation anyway. The jailer came to Paul asking what was necessary to be saved, didn't include baptism, nor were gentiles Peter came to - yet they received the baptism of the Holy Spirit before water baptism.
He both commanded us to be born of the water and of the spirit and was baptized himself.
That baptism wasn't in existance at the time blow - since Christian baptism hadn't yet been instituted. The whole context of this is that the water, refers to the natural birth process.
It makes a clear point, Christ, having no need for baptism was yet baptized. He practiced what he taught.
Ah - there was no Savior nor sacrifice on the cross at that point blow. Jesus was following OT and current Jewish principles and practices at that time. Tell us, unto who was Jesus baptized into? Did Jesus need to be 'saved'. If all that was necessary was a dunking, then Jesus' sacrifice was not necessary - only baptism was needed.
In Matt. 3:15, Jesus tells us that His baptism was "to fulfill all righteousness". The basic action of baptism is identification, so Jesus identified with righteousness in obedience to the Mosaic Law. In Jesus’ day, when a Gentile would convert to Judaism, he would have to be publicly baptized to identify him as a convert. Obviously, Jesus was not converting to anything.
Secondly, Jesus' baptism served as an official and public inauguration of His earthly ministry (John 1:26-27, 31). It was at this time that Jesus was revealed to Israel as their Messiah.