Can you show from the Bible were it specifically says to only baptize adults.
**Nope! That would be like you showing from Scripture that original sin is washed away at infant baptism or for that matter any sin is washed away from water baptism.
But I can show you from Scripture the true Baptism that does save and a little more than that.
Mt 3:11 - "As for me, I baptize you with water for repentance, but He who is coming after me is mightier than I, and I am not fit to remove His sandals; He will baptize you with the Holy Spirit and fire.
Lu 3:16 - John answered and said to them all, "As for me, I baptize you with water; but One is coming who is mightier than I, and I am not fit to untie the thong of His sandals; He will baptize you with the Holy Spirit and fire.
Here we see 2 other baptisms other than water. Note the end of Matthew 3: 11. John says when the Messiah comes, “He will baptize you with the Holy Spirit.” So the second kind of baptism is Holy Spirit baptism. In our reading of baptism in the New Testament, we must continually decide, “Is this passage referring to water baptism or to Holy Spirit baptism?” There are at least eleven references to Holy Spirit baptism in the New Testament. The passage then goes on to talk about judgment in Matthew 3:12, so the baptism of fire may be a reference to the judgment that the Messiah will bring. But the main point to note is that three different kinds of baptism are mentioned here.
Mark 10: 38,39 speaks of a baptism of suffering: “Jesus said to them, ‘You do not know what you are asking for. Are you able to drink the cup that I drink, or to be baptized with the baptism with which I am baptized? ’ And they said to Him, ‘We are able. ’ And Jesus said to them, ‘The cup that I drink you shall drink; and you shall be baptized with the baptism with which I am baptized." He was not talking about water baptism here. That had already taken place. He was talking about something else— probably suffering.
In Acts 19, Paul discovered some disciples of John the Baptist who were still adhering to his message, long after he had been executed (see Acts 19: 1- 6). In Acts 19: 3- 5, Paul asked them, “ ‘Into what then were you baptized? ’ And they said, ‘Into John’s baptism. ’ And Paul said, ‘John baptized with the baptism of repentance, telling the people to believe in Him who was coming after him, that is, in Jesus. ’ And when they heard this, they were baptized in the name of the Lord Jesus.” Note what happened here. Even though these disciples had been baptized with John’s baptism, they are baptized again in the name of Jesus. Obviously, since they were rebaptized, there is a difference or a distinction between the baptism of John and Christian baptism.
The fact that He is about thirty years of age at the time of His baptism is significant because the Old Testament tells us that a male could not begin to carry out his priestly functions until he was thirty years of age. Because Jesus is the Prophet, Priest and King of the nation, it would be fitting for Him to begin His ministry at thirty years of age.
In Matthew 3: 14, as Jesus comes to John to be baptized, note John’s response: “But John tried to prevent Him, saying, ‘I have need to be baptized by You, and do you come to me? ’ ” John realized his need to be identified with Christ, his need to be cleansed by Christ. Jesus’ response is important: “But Jesus answering said to him, ‘Permit it at this time; for in this way it is fitting for us to fulfill all righteousness’ ” (Matt. 3: 15). Jesus recognized that it was right and proper. In fact, it was obligatory for a believer in Israel to be baptized by John. The true believers in the nation Israel were going out to be baptized by John, indicating that they were trusting God and anticipating the coming Messiah to bring in the Kingdom. And now, following His previous pattern of identifying with the nation in important ways, Jesus is baptized by John. In doing so, He identifies Himself with the message of John—“ Repent, for the kingdom of heaven is at hand” (Matt. 3: 2). He identified Himself with the believing remnant in Israel who were prepared for the coming Kingdom. Christ baptism was unique to itself and unrepeatable. A lot more could be said, but not at this time.**