Catholics, Jews, and Protestants

How do you reconcile Revelation 7 and 19 with the church being left behind and not “taken away”? At what point were the Jews no longer doing the right thing with their Temple practices? Also, wasn’t righteousness always by faith anyway? Did Martin Luther delete certain books from the Bible? A Catholic person told me that Protestantism is a cult and that Catholicism is the only true faith. How do I respond to this?

Tags: blood, canon, Catholicism, cross, dividing line, grace, Jesus, Law, left behind, Martin Luther, Mary, mediator, New Covenant, obsolete, Old Covenant, Revelation 19, Revelation 7, saints, taken away