This remark appears in the form of a question to show that Paul is beginning a discussion about the relationship between blessing and circumcision. Alternate translation: "I want to show you how it is that God blesses not only those who are circumcised, but also those who are not circumcised" (See: [[rc://en/ta/man/translate/figs-rquestion]])
You can translate this in an active form. Alternate translation: "God considered the faith of Abraham as righteousness" (See: [[rc://en/ta/man/translate/figs-activepassive]])