Israel was a people chosen by God to know his word and to obey his holy laws. The sign of the covenant was the keeping of the Sabbath. The covenant with Abraham of a land and a people was still in affect. The sign of the Abrahamic covenant was circumcision. Salvation remained by faith in the promises of God. The law was never meant to save you, but was to show the holiness of God. We should strive to be holy as God is holy. The blood sacrifices did not remove sins, but covered them. The blood was looking forward to the coming of the Messiah whose blood was shed to remove our sins, by faith in him. Jesus kept all the laws and is the perfect son of God, our saviour. This web site explains the covenant with Moses better.