Did Paul become an apostle of the Gentiles because of his education or merit?
No. Paul did not claim his apostleship came because he was highly educated, though he had been educated. He also did not claim to be the apostle of the Gentiles because of any personal merit. Instead, he attributed it to the grace of God, saying, "I am what I am."
Les explains that Paul did not base his apostleship on education or merit. The context says believers are what they are not because they have done so much, but because God has done it all. Paul was educated, yet he does not claim that he received his apostleship because of it, nor does he claim to be the apostle of the Gentiles because of merit on his part. Rather, it was by the grace of God: "I am what I am." Les also discusses grace and mercy, defining grace as God's unmerited favor that makes the pouring out of His mercy possible. Since mankind does not deserve mercy, grace is what allows God to show mercy rather than wrath and judgment.
But by the grace of God I am what I am: and his grace which was bestowed upon me was not in vain; but I laboured more abundantly than they all: yet not I, but the grace of God which was with me.