Can Bishops Resign?

“Our Apostles also knew, through our Lord Jesus Christ, that there would be contention over the bishop’s office. So, for this cause, having received complete foreknowledge, they appointed the above mentioned men, and afterwards gave them a PERMANENT character, so that, AS THEY DIED, other approved men should succeed to their ministry.”

Saint Clement, Bishop of Rome, Letter to the Corinthians, Chapter 44. 97 AD

Should a father resign from a family when he is sick? Or tired?

Should our Shepherd  have been replaced on the cross in His darkest hour?