Never heard Luther quote before, but have heard 1 Timothy 3:14–15:
“I am writing these things to you, hoping to come to you before long; but in case I am delayed, I write so that you will know how one ought to conduct himself in the household of God, which is the church of the living God, the pillar and support of the truth.”
And then they poo-poo the following:
Pope Stephen VI (896–897), who had his predecessor Pope Formosus exhumed, tried, de-fingered, briefly reburied, and thrown in the Tiber.[1]
Pope John XII (955–964), who gave land to a mistress, murdered several people, and was killed by a man who caught him in bed with his wife.
Pope Benedict IX (1032–1044, 1045, 1047–1048), who "sold" the Papacy
Pope Boniface VIII (1294–1303), who is lampooned in Dante's Divine Comedy
Pope Urban VI (1378–1389), who complained that he did not hear enough screaming when Cardinals who had conspired against him were tortured.[2]
Pope Alexander VI (1492–1503), a Borgia, who was guilty of nepotism and whose unattended corpse swelled until it could barely fit in a coffin.[3]
Pope Leo X (1513–1521), a spendthrift member of the Medici family who once spent 1/7 of his predecessors' reserves on a single ceremony[4]
Pope Clement VII (1523–1534), also a Medici, whose power-politicking with France, Spain, and Germany got Rome sacked.