Here's Paul in his letter to Timothy:
1 Timothy 2:7
Whereunto I am appointed a preacher and an apostle (I say the truth, I lie not), a doctor of the Gentiles in faith and truth.
Today's Liturgy could be represented in a triptych.
In the center, Jesus, in His boat, on the shore of Galilee, preaches the parable of the sower (Gospel). It is the redeemer Who by His saving doctrine gives life to souls (Collect).
On the left, Noah's ark floats on the waters of the flood (Maitins). It contains the family, which is to repopulate the world with believing souls.
On the right, St. Paul faces sipwreck and "the perils of the sea" (Epistle) in order that all nations(Collect) may hear the life giving word of Christ. So the staton is at St. Paul-outside-the walls, and in the Mass his memory occupies a large place.
- Dom Gaspar LeFebvre