Don't Mean to Get All Churchy on Ya

I do try to read a little scripture every day, although it's usually the low-quality type of study we are encouraged not to do. There is a little bit of excitement whenever a short chapter comes up in my scriptural queue. Something like say, Mosiah 6, which is all of seven verses. If most people were asked what is in Mosiah 6, they wouldn't be able to tell you. Me included, before this time. I decided to read the seven verses keeping an eye out for what is significant about the chapter.

I found the first two verses to be interesting:

And now, king Benjamin thought it was expedient, after having finished speaking to the people, that he should take the names of all those who had entered into a covenant with God to keep his commandments.

And it came to pass that there was not one soul, except it were little children, but who had entered into the covenant and had taken upon them the name of Christ.

So the whole bit about everyone entering into a covenant with God to keep his commandments (save little children) - it sounds a lot like baptism. In fact, if you go back and look at Mosiah 5, it is basically a discussion of the people entering into a covenant and what the covenant meant - phrases such as "born of him" and "called by the name of Christ" are used. It sounds pretty much like the baptismal covenant which is more famously laid out a few pages later in Mosiah 18.

The interesting thing about Mosiah 5 and 6 - although it talks a lot about the covenant, words such as "baptism" and "water" are never used.

So my question is - when did the Nephites begin practicing baptism by immersion as the accompanying ordinance to the baptismal covenant?

Any mentions of baptism before Mosiah 18 seem to be either prophetic references or commandments to be baptized - there are no firsthand accounts. And even the Mosiah 18 story is a bit unusual. Upon performing his first baptism, Alma also immerses himself in the water. It isn't made clear why he does this - whether it's the fact that he had never been baptized himself or if it was some sort of do-over for his years as one of the wicked priests under King Noah. Either way, Alma apparently had the priesthood authority to perform baptism.

Post Mosiah 18, we read more frequent accounts of baptism. So either Alma pioneered the doctrine of baptism among the Nephites, or it was practiced all along but never explicitly mentioned. I'm not sure. I guess I'm still in the "pondering" phrase of study. I haven't prayed about it because the answer wouldn't seem to have any impact on my own salvation - it's basically just a curious matter, kind of like when back in the day groups of missionaries would sit around and try to trace the line of priesthood authority among the Nephites.