In Galatians 3:23, Paul writes that “before faith came, we were kept under the law.” By “we” Paul is referring to the Jewish believers in the Galatian churches. They are the ones acquainted with the law, and Paul has been speaking to them in particular since Galatians 2:15. This can be seen in the contrast between the “we” in Galatians 3:23 and the “you” in Galatians 3:26 (ESV).
Galatians 3:23 reads, “Before faith came”; but in the literal Greek it reads, “before the faith” came. Because Paul is contrasting the place of the law before and after Christ (Gal. 3:24), “the faith” is most likely a reference to Jesus Himself and not a reference to Christian faith in general.