Paul wishes to emphasize the truth that Christ is not divided but one. "It is not possible to divide Christ in the way you are doing!" (See: [[rc://en/ta/man/translate/figs-rquestion]] and [[rc://en/ta/man/translate/figs-activepassive]])
Paul wishes to emphasize that it was Christ, not Paul or Apollos, who was crucified. This can also be translated in active form. AT: "It certainly was not Paul whom they put to death on the cross for your salvation!" (See: [[rc://en/ta/man/translate/figs-rquestion]] and [[rc://en/ta/man/translate/figs-activepassive]])
Paul wishes to emphasize that we all are baptized in the name of Christ. This can also be translated in active form. AT: "It was not in the name of Paul that people baptized you!" (See: [[rc://en/ta/man/translate/figs-rquestion]] and [[rc://en/ta/man/translate/figs-activepassive]])
"In the name of" is a metonym for "by the authority of" AT: "It was not by the authority of Paul that people baptized you!" (See: [[rc://en/ta/man/translate/figs-metonomy]])