Orientale Lumen 20, Pope John Paul II, 1995

[T]he Church of Rome has always felt was an integral part of the mandate entrusted by Jesus Christ to the Apostle Peter: to confirm his brothers in faith and unity (cf. Lk 22:32). Attempts in the past had their limits, deriving from the mentality of the times and the very understanding of the truths about the Church. But here I would like to reassert that this commitment is rooted in the conviction that Peter (cf. Mt 19:17 – 19) intends to place himself at the service of a Church united in charity. “Peter’s task is to search constantly for ways that will help preserve unity. Therefore he must not create obstacles but must open up paths. Nor is this in any way at odds with the duty entrusted to him by Christ: ‘strengthen your brothers in the faith’ (cf. Lk 22:32). It is significant that Christ said these words precisely at the moment when Peter was about to deny him. It was as if the Master himself wanted to tell Peter: ‘Remember that you are weak, that you, too, need endless conversion. You are able to strengthen others only insofar as you are aware of your own weakness. I entrust to you as your responsibility the truth, the great truth of God, meant for man’s salvation, but this truth cannot be preached or put into practice except by loving.’

(Emphasis mine)