***You even quoted the verse that tells us why that seemed a prudent thing for Paul to do. **
Do you have a problem that “by works a man is justified” JAMES, the leader of the Jerusalem CHRISTIAN Church telling Paul to go offer sacrifices in the Temple? WHY were the Jerusalem Christians still offering animal sacrifices!
And if I wanted to change the subject I would mention that other bugbear (gasp)INSTRUMENTAL MUSIC or kitchens in the church building or a half dozen other doctrines that separate five little Campbellite churches in this area.
Quite a few web pages point to Nicander (200BC) writing of making pickles by plunging, and removing(bapto) into boiling water, then Baptizing(Baptizo) them in vinegar.
St Paul states: 1Corinthians 12:13:
For by one Spirit are we all baptized (baptizo) into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.
Again, water baptism is still after the fact that the person is saved. Same as Cornelius was saved before his in and out water baptism.
.