Ss. Peter and Paul by Bartolomeo Vivarini
Almighty God, whose blessed apostles Ss. Peter and Paul glorified thee by their martyrdom: Grant that thy Church, instructed by their teaching and example, and knit together in unity by thy Spirit, may ever stand firm upon the one foundation, which is Jesus Christ our Lord; who liveth and reigneth with thee, in the unity of the same Spirit, one God, for ever and ever. Amen.
Basilica of St. Peter, Vatican City State
"Both apostles share the same feast day, for these two were one; And even though they suffered on different days, they were as one. Peter went first, and Paul followed. And so we celebrate this day made holy for us by the apostles' blood. Let us embrace what they believed, their life, their labors, their sufferings, their preaching, and their confession of faith."
St. Augustine of Hippo, Sermon 295