Ex cathedra is a Latin phrase which means "from the chair." It refers to binding and infallible papal teachings which are promulgated by the pope when he officially teaches in his capacity of the universal shepherd of the Church a doctrine on a matter of faith or morals and addresses it to the entire world.
Only God alone is a Law giver of the Church in matter of faith or moral laws not the pope.
God alone, who gave the law, is the Judge. He alone has the power to save or to destroy..."(James 4:12)
From the Chair of Scoffer:
Blessed is the man who walks not in the counsel of the wicked, nor stands in the way of sinners, nor sits in the seat of scoffers;(Psalms 1:1)