1. If something is true, then like God it always was and always will be. It remains true no matter what.
2. A good tree cannot bear forth bad fruit, a bad tree cannot bear forth good fruit.
3. In the Old Testament sacrifices by the Jews were made to appease God, but nothing would atone for original sin (bc it carries infinite demerits against the infinitely good Creator), except an infinite and perpetual sacrifice, which only God the Son could offer, the Holy Sacrifice of the Mass is exactly that, the crucifixion of Christ offered back to the Father in an unbloody manner instituted by Christ Himself