From the homily of Pope Francis on this day, 2020
“We celebrate together two very different individuals: Peter, a fisherman who spent his days amid boats and nets, and Paul, a learned Pharisee who taught in synagogues. When they went forth on mission, Peter spoke to Jews, and Paul to pagans. And when their paths crossed, they could argue heatedly, as Paul is unashamed to admit in one of his letters (cf. Gal 2:11). In short, they were two very different people, yet they saw one another as brothers, as happens in close-knit families where there may be frequent arguments but unfailing love. Yet the closeness that joined Peter and Paul did not come from natural inclinations, but from the Lord. He did not command us to like one another, but to love one another. He is the one who unites us, without making us all alike. He unites us in our differences.
“Today’s first reading brings us to the source of this unity. It relates how the newly born Church was experiencing a moment of crisis: Herod was furious, a violent persecution had broken out, and the Apostle James had been killed. And now Peter had been arrested. The community seemed headless, everyone fearing for his life. Yet at that tragic moment no one ran away, no one thought about saving his own skin, no one abandoned the others, but all joined in prayer. From prayer they drew strength, from prayer came a unity more powerful than any threat.
“Let us notice something else: at that dramatic moment, no one complained about Herod’s evil and his persecution … It is pointless, even tedious, for Christians to waste their time complaining about the world, about society, about everything that is not right. Complaints change nothing. Let us remember that complaining is the second door that closes us off from the Holy Spirit … The first is narcissism, the second discouragement, the third pessimism. Narcissism makes you look at yourself constantly in a mirror; discouragement leads to complaining and pessimism to thinking everything is dark and bleak. These three attitudes close the door to the Holy Spirit. Those Christians did not cast blame; rather, they prayed. In that community, no one said: “If Peter had been more careful, we would not be in this situation”. No one. Humanly speaking, there were reasons to criticize Peter, but no one criticized him. They did not complain about Peter; they prayed for him. They did not talk about Peter behind his back; they talked to God. We today can ask: “Are we protecting our unity, our unity in the Church, with prayer? Are we praying for one another?” What would happen if we prayed more and complained less?”
Obtained from https://www.ccvichapel.org/post/feast-of-saints-peter-and-paul-fiesta-de-los-santos-pedro-y-pablo