In Luke 22:31-32, Jesus said to Peter, the chief steward of his Church, “Simon, Simon, behold, Satan demanded to have you [all], that he might sift you [all] like wheat, but **I have prayed for you [Peter] that your **faith may not fail; and when you [Peter] have turned again, strengthen your brethren.”
Since Satan will be an ever-present threat to the Church until the Last Day, the chief stewards of the Church, the popes, as Peter’s successors, of necessity must also enjoy the fruits of Jesus’ prayer for Peter, faith that will not fail.