Fulfillment. Everything that was anticipated in the jewish religion is fulfilled in the Catholic Church. The plan for judaism was as a preparation, a seed in anticipation of the flowering that would come with Christ, in this sense they are not two seperate things but rather different stages in a universal plan for humanity. I am not saying grace has to be renewed in the Eucharist (and the other sacraments), I am saying it has to be received in the sacraments. The sacraments must be recieved regularly and with perseverance because grace can be lost through sin and thus a regular and direct communion with Christ in the eucharist is necessary. This is to strengthen the soul and sanctify it further into ever closer conformity to Christ. This is also very practical in regards to avoiding sin, as if you are always to be prepared for recieving Christ into your house in ancticipation of the mass and the eucharist, one always has in mind the cultivation of his own holiness so that his soul and his house may be ready for Christs reception. As to redemption, man is already redeemed, the door is opened. It is not a matter of redeeming himself again. However man still has to walk through the door. Salvation is a process and not a singular event, one still has to walk along the winding path and through the narrow gate to get to heaven, its not a matter of Christ teleporting you from the bottom to the top in a single instant because the end-point of salvation is when your through the gate, when your in heaven. As to faith and works. You have a wrong definition of faith. Faith does not equal belief. True faith includes action and belief in one coherent whole, one is not the product of the other. If you have faith then that faith is lived in action. If not than you lack faith and merely have belief for as it is written, Faith without works is dead, this is because the two are in fact one and indivisable. One final thing. Of course it makes sense, although you still do not comprehend fully. Christianity (well at least Catholic Christianity) is the faith according to reason. It is the religion of the Logos!