Mark 1v8

I indeed have baptized you with water: but he shall baptize you with the Holy Ghost.

These words of John the Baptist show the progression of revelation regarding baptism. John’s revelation was to baptize with water, but the one to come – later revealed to be Jesus – was going to carry this a stage further, bringing the Holy Ghost/Holy Spirit in as part of baptism.

See also Matthew 3v11 {4 } for further discussion of this prophecy of John’s.