That statement makes a lie of 1 Pet 3:21, Acts 8:36, Matt 28:19, and other passages. Your doctrine must be true to ALL Scripture.
No, you simply misinterpreted those verses.
In
1 Peter 3:21, Peter tells us that baptism now saves you, yet when Peter uses this phrase
he continues in the same sentence to explain exactly what he means by it. He said that baptism now saves you-
not the removal of dirt from the flesh (that is, not as an outward, physical act which washes dirt from the body--that is not what saves you),
"but an appeal to God for a good conscience, through the resurrection of Jesus Christ" (that is, as an inward, spiritual transaction between God and the individual, a transaction that is
symbolized by the outward ceremony of water baptism).
Just as the eight people in the ark were "saved THROUGH water" as they were IN THE ARK. They were not literally saved "by" the water.
Hebrews 11:7 is clear on this point (..built an
ARK for the
SAVING of his household). *The context reveals that ONLY the righteous (Noah and his family) were DRY and therefore SAFE. In contrast,
only the wicked in Noah's day came in contact with the water and they all perished.
*So, by Peter saying, "not the removal of dirt from the flesh, but an appeal to God for a good conscience - through the resurrection of Jesus Christ," Peter guards against saving power to the physical ceremony in H20.
In regard to Acts 8:36, the eunuch was saved when he believed in Jesus Christ (compare with John 20:31) before he was water baptized.
In regard to Matthew 28:19, we have here a command from Jesus here to go and make disciples of all nations and baptize them. However, it does not say here that baptism is absolutely necessary for salvation.
Also, see post #113.