I think also that we misrepresent Judaism, at least prior to Jesus Christ, if we remove the central element of faith. Certainly there had always been the legalists, as there are today, both in and out of Catholicism, but a close look at the progress of God’s Revelation to Israel, starting way back with Abraham, reveals that God was teaching faith along with the Law, the Law being the means by which Israel knew their own sin, their formation of conscience we might say, and also their moral guide for everyday living.
But the great elaborate system of sacrifice was precisely there because people were not able to keep the moral Law perfectly, anymore than we are able today. They needed the means to reconcile with God. And, as we know, those sacrifices all point toward Christ who is the last and complete blood sacrifice for sin, the perfect first-born without blemish, the Lamb of God.
To speak of the Law as what saves a man prior to Christ, is to miss the sacrificial part of that Covenant with God. Of course the Law in and of itself, as prescriptive, could not save a man, but the means was there, pointing to the ultimate sacrifice to come. In that way we see that the Jews needed to have faith in God, and it was when they lost that faith, that trust, that they found themselves under the heel of one tyrant or another.
That is at least part of what Jesus meant when he said that he had not come to abolish the Law but to fulfill it. Paul says in various places that the Law is good. Clearly, he is talking about the moral law, because the sacrificial system was now gone for Christians, replaced by Christ’s sacrifice which we enter into at Mass, and in ministering to Gentiles Paul was also in concert with Peter and the decision taken at Jerusalem to relieve Gentile Christians of the dietary requirements of Judaism.
It is a mistake then to think that before Jesus the people of God worked their way into favor with God and that afterward it is all faith. Faith was also there before Christ, but now we have the person of the Holy Spirit to help us from within, to fulfill the moral law, grace flowing in abundance through the sacraments of the Church, to not only reconcile us with God but enable us to do the works of Christ and have merit attributed to us for those works done in the power of grace. He enables us and then gives us the credit! How abundantly generous is our God!