“Alas, Most Holy Father!  At times, obedience to you leads to eternal damnation.”
St. Catherine of Siena, Letter to Pope Gregory XI

There are so many people whose heads would explode if they read this quote.

Is St. Catherine speaking of the eternal damnation of the pope or of the eternal damnation of those who obey him?

Matthew 18:6
"But he that shall scandalize one of these little ones that believe in me, it were better for him that a millstone should be hanged about his neck, and that he should be drowned in the depth of the sea."

While this is describing what happens to those who lead children astray, this easily applies to leaders as well.