The Catholic Catechism says of baptism, for example: “Baptism not only purifies from all sins, but also makes the neophyte 'a new creature,' an adopted son of God, who has become a 'partaker of the divine nature,' member of Christ and co-heir with him, and a temple of the Holy Spirit” (Catechism 1265).
Yet it was Peter who they claim was the first Pope who said the opposite.
1 Pet 3:21 There is also an antitype which now saves us-- baptism (not the removal of the filth of the flesh, but the answer of a good conscience toward God), through the resurrection of Jesus Christ,
The filth of the flesh is the sin nature. Baptism according to Peter does not remove this, he also calls it an antitype, which is a type of another type. This proves it is a symbol of the real event.
The Bible teaches that it is the blood of Jesus that can only take away sin.
Luke 22:19-20 And He took bread, gave thanks and broke it, and gave it to them, saying, “This is My body which is given for you; do this in remembrance of Me.” Likewise He also took the cup after supper, saying, “This cup is the new covenant in My blood, which is shed for you.