The earliest record of baptism in the NT is the baptism of John. It was the baptism of repentance for the remission of sins. Was it in the spirit or in water? It was water baptism, and in the Jordan River. This is identical to the baptism recorded in Acts 2:38 except it was in the name of Jesus Christ, for repentance, for the remission of sins, to receive the Holy Ghost, and to be added to the church by the Lord (verse 47). Hence, the need for the Ephesians to be re-baptized as recorded in Acts 19. All baptisms can or should be assumed to be water baptism unless otherwise stated, and those are clearly otherwise stated in scripture. Why would anyone assume anything different? On what basis, other than anti-baptism bias? How can one ignore scriptures such as Acts 22:16 or the account of the conversion of the Ethiopian eunuch in Acts 8? Clearly, baptism is in water unless otherwise stated in scripture, and the account in Acts 8 also indicates that Philip obviously included the need for water baptism as part of his preaching of the gospel to the eunuch.
Luke 3:3
3And he came into all the country about Jordan, preaching the baptism of repentance for the remission of sins;
Mark 1:4-5
4John did baptize in the wilderness, and preach the baptism of repentance for the remission of sins.
5And there went out unto him all the land of Judaea, and they of Jerusalem, and were all baptized of him in the river of Jordan, confessing their sins.
Acts 22:16
16And now why tarriest thou? arise, and be baptized, and wash away thy sins, calling on the name of the Lord.
Acts 8:36-38
36And 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?
37And 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.
38And he commanded the chariot to stand still: and they went down both into the water, both Philip and the eunuch; and he baptized him.