They HAD to be water baptized.
Before any of those who lived under the law could be baptized with water they had to believe, as witnessed by the following exchange between Philip and the eunuch:
"And as they went on their way, they came unto a certain water: and the eunuch said, See, here is water; what doth hinder me to be baptized? And Philip said, If thou believest with all thine heart, thou mayest. And he answered and said, I believe that Jesus Christ is the Son of God" (Acts 8:36-37).
Before the eunuch was baptized with water he was already "born of God" because he believed that Jesus is the Christ, the Son of God:
"Whosoever believeth that Jesus is the Christ is born of God..For whatsoever is born of God overcometh the world: and this is the victory that overcometh the world, even our faith. Who is he that overcometh the world, but he that believeth that Jesus is the Son of God?" (1 Jn.5:1,4-5).
There can be no doubt that the eunuch received eternal life and was "born of God" before he was baptized with water so we can know that being baptized with water does not contribute in any way to anyone being saved. If you are born of God you would understand these things but unfortunately you remain a natural man who is unable to understand spiritual things.
Besides that the lord Jesus told the Jews who lived under the law that His words are spirit and they are life:
"It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life" (Jn.6:63).
According to you His words by themselves were insufficient to bring spiritual life to the Jews who lived under he law because you deny that those who believed were saved by faith alone.
You call yourself a Christian but you deny Christ's own words over and over and over again. You are an embarrassment to those who actually believe what the Lord Jesus taught.