Romans 3:25-26 :
whom God set forth to be an atoning sacrifice, through faith in his blood, for a demonstration of his righteousness through the passing over of prior sins, in God’s forbearance; to demonstrate his righteousness at this present time; that he might himself be just, and the justifier of him who has faith in Jesus.
God used to overlook sin. According to this passage, it was only His patience that held God back long enough for the time when He would be the one who would take care of our sin problem. The Jewish animal sacrifices were not able to really clean a person of their wrong. God was just “passing over” their sins.
It was God’s intention to make His own demonstration of righteous that we would be required to have faith in. It is only God who is good and who makes us good and it is only done by faith in Jesus Christ.
Notice that this does not leave any room for any other religion. The only hope offered to anyone in Christianity is Christ. He is the only demonstration of true righteousness. No man and no thing can take His place.