This can be translated in active form. Here the words "by faith" refers to either 1) the means by which God justifies a person. Alternate translation: "God justifies a person through that person's faith" Or 2) the reason for which God justifies a person. Alternate translation: "God justifies a person because he has faith" Faith is not the actor that justifies a person. (See: [[rc://en/ta/man/translate/figs-activepassive]])