Water baptism.
I see it in the OT When Moses was told to take Arron and his sons to the Jordan, And WASH them.
It was a way in which God was introducing to the children of Israel he was setting these men apart as priests. It did not cleans their sins, (they still had to cleans themselves if they were to enter the inner sanctuary ore do other priestly duties) It did not save them ( I know of no one who thinks ciaphis was saved, let alone many priests who rejected Gods way)
We also know a Gentile, if he or she was converting to Judaism, was to also go through a "washing" ceremony, Which would be seen as an OT form of baptism. We know this also did not cleans anyone sins, or save anyone, It was just a ceremony to introduce to people that these individuals chose to deny their gentile Gods and follow the God of Israel.
We also know. Jesus himself was baptised. The reaon John the baptist was sent to prepair the way. He was told. He whom you baptise and immediately comming out of the water, the spirit descending as a dove, is the messiah. Jesus had no sin to be washed, He was already pure. Nore did he need to be saved, He was pure.. he did it, As Moses did Arron, to be revealed to the children of Israel. This is your messiah..
Tody, Christians are all told to be batized in water, in the great commission. Jesus told the disciples to go make other disciples. and baptize THEM. Just like all the OT examples though. We know it does not wash away any sin, and does not save anyone, It is a way to be a witness, that you to are set apart for God, saved by God, and made priests unto him, also a way of oepn testimony of a person fatih and decare it to the word. Which in all OT cases was the same..