Is there any consequence for not being baptized? Jesus speaks clearly to that in John 3.
Now there was a Pharisee, a man named Nicodemus who was a member of the Jewish ruling council.
2 He came to Jesus at night and said, “Rabbi, we know that you are a teacher who has come from God. For no one could perform the signs you are doing if God were not with him.”
3 Jesus replied, “Very truly I tell you, no one can see the kingdom of God unless they are born again. ”
4 “How can someone be born when they are old?” Nicodemus asked. “Surely they cannot enter a second time into their mother’s womb to be born!”
5 Jesus answered, “Very truly I tell you, no one can enter the kingdom of God unless they are born of water and the Spirit.
Some of my dear friends are trying to persuade me that born of water should not be taken literally. The phrase born of water appears only this once in the whole bible. It is my understanding that if God wanted us to understand this to mean something else, the same phrase would have been used elsewhere where the context would have brought out the meaning God intended. In this case the one occurrence leaves us with just the literal meaning which fits perfectly with the rest of the bible.
Jesus showed how important baptism (or water) is when He insisted that John must baptize Him:
13 Then Jesus came from Galilee to John at the Jordan to be baptized
by him. 14 And John tried to prevent Him, saying, “I need to be
baptized by You, and are You coming to me?”
15 But Jesus answered and said to him, “Permit it to be so now, for
thus it is fitting for us to fulfill all righteousness.” Then he
16 When He had been baptized, Jesus came up immediately from the
water; and behold, the heavens were opened to Him, and He[a] saw the
Spirit of God descending like a dove and alighting upon Him. 17 And
suddenly a voice came from heaven, saying, “This is My beloved Son, in
whom I am well pleased.” Matthew 3:13-17
And soon after His resurrection, Jesus made it clear that baptism (of water) is important:
15 And He said to them, “Go into all the world and preach the gospel
to every creature. 16 He who believes and is baptized will be saved;
but he who does not believe will be condemned. Mark 16:15,16
Paul shows the rich symbolism the baptism has in the journey of a Christian.
The act of being baptized shows that we can actually participate in the death, burial, and resurrection of Jesus. Baptism means that we have died with Christ, and have buried the old life of sin with Christ, and that we are rising to "live a new life" in Christ:
3 Or do you not know that as many of us as were baptized into Christ
Jesus were baptized into His death? 4 Therefore we were buried with
Him through baptism into death, that just as Christ was raised from
the dead by the glory of the Father, even so we also should walk in
newness of life. Romans 6:3,4
Note: The gospels and Acts refer to water baptism as the baptism of John or the baptism of repentance to differentiate it from the baptism of the Spirit/Fire:
Matthew 21:25, Mark 1:4, Mark 11:30, Luke 7:29, Luke 20:4, Acts 1:22, Acts 13:24, Acts 18:25, Acts 19:4.