At birth there are three entities present: water, blood, and the Spirit.
At baptism there are three entities present: water, blood, and the Holy Ghost.
At the crucifixion there was water and blood spilling from the side of the Savior to indicate death. His Father had left Him, the Holy Spirit was 50 days away and the Last Supper typed of our new birth and covenant.
Baptism is a death, a burial, and a resurrection.