there is an abundant scholarly literature discussing the influence of ancient philosophy on the thinking of Paul.
Troels Engberg-Pedersen: Paul and the Stoics
Th. D. Niko Huttunen: Paul and Epictetus on Law
Abraham J. Malherbe: Paul and the Popular Philosophers
Engberg-Pedersen sees remarkable similarities between the Stoic concept of Logos/Reason and Paul’s concept of Christ as a life-changing power, specifically “from above”, “in whom” the convert dwells. (Compare the expressions “in Christ”, “Christ in you”.)
Huttunen argues for Paul’s debt to Stoicism for much of his theological teachings about the law. (This Stoic model was indebted ultimately to Plato and his discussion of ethics and the good life in his Republic.)
Modern scholarship was not the first to discover Paul’s indebtedness to Greek culture. His letters, even on a superficial level, have many affinities with the popular philosophy of his day, especially as it was represented by Stoicism and Cynicism. . . .
During the last hundred years, New Testament scholars have shown that many aspects of Paul’s life and letters are illuminated with they are examined in the light of Greco-Roman culture. There can no longer be any doubt that Paul was thoroughly familiar with the teaching, methods of operation, and style of argumentation of the philosophers of the period, all of which he adopted and adapted to his own purposes. . . .
The points of similarity between Paul and his philosophic competitors may be stressed to the point that he is viewed as a type of hellenistic philosopher. (pp. 67-68)
Peter, Paul, and Mary Magdalene, pp. 103, 107:
[A]s a Jew in the Diaspora, Paul would have been surrounded by people embracing religions other than Judaism. Paul, unlike Jesus or Peter, was raised in a non-Jewish, “pagan” environment. . . .
Paul actually came from a Greek-speaking, rather than Aramaic speaking, environment. . . . It is clear that Paul must have come from some relatively large urban setting in the Jewish Diaspora, and this may have been Tarsus. . . . Tarsus was known as one of the great philosophical centers of the empire, one of the two or three best places for a person to develop his philosophical and rhetorical abilities. . . .