Jesus is the author of eternal salvation to all those who obey Him. (Heb. 5:9)
Obedience here is to obey the gospel message; that is, to believe in Jesus as the Son of God, who died for our sins and saves those who believe in Him.
Nothing more.
In Mark 16, Jesus said he who believes and is baptized shall be saved. He did not say be saved by believing and afterward get baptized.
So, the verses aren't inspired by the Holy Spirit.
However, even though added by a later scribe, how does anyone know whether the scribe was referring to the baptism of the Holy Spirit, which doesn't even include water immersion at all?