Two great pillars of the first century church, the New Testatment does not depict them in close union. Each is clearly gifted, each is committed to serving Christ - and each is just as clearly headstrong and stubborn.
According to Paul (in Galatians 2), Peter extended the hand of fellowship and affirmed Paul's ministry to the gentiles. Yet they clashed in Antioch over Peter's equivocation about breaking the boundaries between Jew and gentile.
It may well be that they had different visions for the Jesus-movement that would later grow into a Jewish-derived but non-Jewish "church." It may also be that two strong egos had a bit of rivalry.
Yet the church put them together at an early date, commemorating this as the date of their martyrdom. This is something they unambiguously shared. Tradition has them both dying in Rome, Paul beheaded, and Peter crucified upside down. Whatever their differences in life, whatever their arguments about the faith, their lives both bore witness to the truth they knew in Jesus Christ.
Martyrdom of Saint Peter and Martyrdom of St. Paul.
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Holy God, your mercy is as boundless as your compassion for your people. Grant that, whatever our circumstances, we may know your reconciling love in this life and the next, and give witness to your saving power, known by Peter, Paul, and all the saints, through Jesus Christ our Lord. Amen.