Baptism is understood by people in John the Baptizer’s day as referring to the cleansing of sin, making one ceremonially pure.
But looking forward, the Gospels show us something more is coming.
The Bible progressively reveals things. What came before isn’t bad, it was just a beginning. It’s the cute stories you hear in Sunday School as opposed to the in-depth Bible study you hopefully get at Big People Church.
You start small and build. It’s how you educate any kid. One way to look at the Bible and its progression is as a book a parent, say a Heavenly Father, writes to His kids, humanity. View Humanity as God’s kid that God is teaching. The Bible starts with pictures and illustrations and builds into doctrine.
The two fuller pictures that baptism represents are hinted at several times.
In Mark 1:8, John the Baptizer says, “I baptize you with water, but he will baptize you with the Holy Spirit.”
The “he” refers to Jesus. The same context has John saying Jesus is better than him, he’s not even worthy to take off Jesus’ sandals. Jesus is better, so too is Jesus’ baptism.
John clearly is pointing people forward to something better, not dunking in water, but being immersed in and filled with the Spirit.
Later on (Mark 10:37-40), James and John ask Jesus if they can have good seats in the Kingdom. Jesus says to them, “Can you drink the cup I drink or be baptized with the baptism I am baptized with?”
They, of course, answer immediately, “Well, yeah, I’m sure we can. Duh, how hard is that?” And Jesus says “You will drink the cup I drink and be baptized with the baptism I am baptized with.”
Something bigger is going on here. They are hearing ”dunked in water;” Jesus is referring to something else.
His use of “cup” is enlightening. Jesus refers to His death using this idea, “If it be possible, let this cup pass from me.”
Baptism here seems to be referring to the death of Jesus Christ. They will feel pain for following Christ.
The two fuller truths that baptism signifies are receiving the Spirit and identification with the death of Jesus Christ.
If you pick up on these things here, more New Testament passages about baptism will make sense.