Struthio, if you don't believe that justification was possible in the OT, then you don't believe that the OT sacrifices could forgive sins. But they could and did. They were a prefigurement of the Mass and Christ's sacrifice. It was a prefigurement of confession, when the jews had to offer sacrifices for specific sins. Forgiveness of sins and the state of grace were certainly possible in the OT. Trent's teachings applicable to the New Law, to the Church - not to the Old Law.