In my view, Paul isn't describing a reality that only takes place in the mind of God. He has employed the rite of baptism in a metaphor to indicate the attitudes and beliefs of those who have become disciples of Jesus. In order to see his point, we need to understand what baptism meant to his generation.
Your thread isn't asking whether or not someone should be baptized. I, for one, encourage people to get baptized and I created a video to defend it. Nonetheless, your question is why churches today are not baptizing people anymore, and to answer that question I observe that the ritual of baptism no longer has the meaning it did in Paul's day. Baptism today, in some churches, has a completely different meaning than the Biblical meaning of Paul's day. And for this reason, I can understand why some people and some churches have stopped doing it.
I was trying to get you to understand the Biblical meaning of baptism, which is not a mystical death-burial-and-resurrection experience. Paul isn't making that claim and he isn't teaching that idea.
Now, did Peter exhort Israel to be water baptized in the name of Jesus Christ? Yes. But what did he mean by that? What was the cultural significance of being baptized in water in the name of someone? How can we know what ideas were implied or suggested by the term "baptism" during Peter's time? To answer that question, I took you to acts 19, wherein we gain a window into the implied significance of water baptism from Paul's conversation with several of John's disciples. In that context we come to understand that when someone is "baptized into" John, he is being immersed in John's teaching. Those who were water baptized by John, became John's disciples, dedicating themselves to both learn and live by his teachings.
Now that we have a better understanding of what baptism actually meant and what it implied, we are in a good place to understand what Peter meant by his exhortation to "be baptized in the name of Jesus Christ for the forgiveness of your sins." Becoming a disciple of Jesus Christ, believing in him, trusting him, learning from him, and walking according to his teaching is the sum and substance of Peter's exhortation. If this is the reason why someone wants to be water baptized, then I say go for it. But if water baptism means something other than that to you, then I say your wasting your time.
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p.s. I'm not talking about you specifically. I meant "whoever".
I agree, Baptism in the name of Jesus means to be immersed in the teaching of...(but not strictly/only).
Now, within the "teaching of Jesus Christ" - water baptism is preached...
Acts 8:30 And Philip ran thither to him, and heard him read the prophet Esaias, and said,
Understandest thou what thou readest?
Acts 8:31 And he said, How can I,
except some man should guide me? And he desired Philip that he would come up and sit with him.
Acts 8:35 Then Philip opened his mouth, and began at the same scripture,
and preached unto him Jesus.
Acts 8:36 And as they went on their way, they came unto a certain water: and the eunuch said, See,
here is water; what doth hinder me to be baptized?
Note: That verse does not say, behold here is water;
what doth hinder me to be to be immersed in the teaching of?
Here is another account of preaching "Jesus" and water baptism is preached...
Acts 16:30 And brought them out, and said,
Sirs, what must I do to be saved?
Acts 16:32 And they
spake unto him the word of the Lord, and to all that were in his house.
Acts 16:33 And he
took them the same hour of the night, and washed their stripes; and was baptized, he and all his, straightway.
Acts 16:34 And when he had brought them into his house, he set meat before them, and rejoiced, believing in God with all his house.
The question is, why is water baptism so important?...
Jesus said, Verily, verily, I say unto thee, Except a man be born of
water and of the Spirit,
he cannot enter into the kingdom of God. (John 3:5)
Peter said, Repent, and be
baptized every one of you in the name of Jesus Christ
for the remission of sins, and ye shall receive the gift of the Holy Ghost.
And also Ananias said to Paul, And now why tarriest thou? arise, and be
baptized, and
wash away thy sins, calling on the name of the Lord.