{Because} (dioti, again, dia, hoti). {By the works of
the law} (ex erg(936e) nomou). "Out of works of law." Mosaic law
and any law as the source of being set right with God. Paul
quotes  Ps 43:2  as he did in  Ga 2:16  to prove his point. {The
knowledge of sin} (epign(9373)is hamartias). The effect of law
universally is rebellion to it ( 1Co 15:56 ). Paul has shown this
carefully in  Ga 3:19-22 . Cf.  Heb 10:3 . He has now proven the
guilt of both Gentile and Jew.