Paul uses this rhetorical question to show the evidence that he is not proclaiming circumcision. This can be expressed as a statement. Alternate translation: "Brothers, you can see that I am not proclaiming circumcision because I am still being persecuted." (See: [[rc://en/ta/man/translate/figs-rquestion]] and [[rc://en/ta/man/translate/figs-hypo]])
"if I still proclaim that men have to be circumcised"
# why am I still being persecuted?
This can be expressed in active form. Alternate translation: "why are the Jews still persecuting me?" (See: [[rc://en/ta/man/translate/figs-activepassive]]
Paul is describing a situation that has not happened as evidence that he does not preach circumcision. Since the stumbling block of the cross has not been removed, that is evidence that Paul does not preach circumcision. (See: [[rc://en/ta/man/translate/figs-hypo]])
This can be expressed without the passive form. Alternate translation: "the cross would no longer be a stumbling block" or "the cross would no longer cause people to stumble" (See: [[rc://en/ta/man/translate/figs-activepassive]])
Here the words "stumbling block" are a metaphor for something that angers or offends some people and leads them to reject the truth. In this case, teaching that people are saved by "the cross" offends those who believe a person is saved by obeying the law. These people "stumble" when they reject the teaching about the cross. (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here "the cross" is a metonym for the teaching that because Jesus died on the cross and is alive again, people are saved by believing in him alone. Alternate translation: "the message about the cross" (See: [[rc://en/ta/man/translate/figs-metonymy]])