CLAIM: Some Calvinist interpreters hold that this passage supports the notion that God predestines humans for heaven or hell, while they are still in their “mother’s womb.” Is this the case?
RESPONSE: A number of observations can be made.
First, this passage strictly refers to Paul, rather than all people. Therefore, at most, this passage shows that God worked this way in the life of Paul (c.f. Jer. 1:5).
Second, this passage teaches that Paul was chosen for the purpose of ministry, rather than the purpose of heaven or hell. If we stick strictly to the text, we see that God chose Paul “so that [he] might preach Him among the Gentiles” (Gal. 1:16). Therefore, the purpose of Paul’s calling was for the purpose of ministry—not for the purpose of heaven or hell.
Third, Acts teaches that Paul had a choice regarding his heavenly vision. Paul told Agrippa that he did “not prove disobedient to the heavenly vision” (Acts 26:19). Moreover, while in Acts 9 Jesus appears to override Paul’s freewill decision, Paul’s later testimony tells us that there was a three day delay in him coming to faith. After three days of contemplating, Ananias said, “Now why do you delay? Get up and be baptized, and wash away your sins, calling on His name” (Acts 22:16).
Fourth, Paul brings this up to demonstrate the authority of his gospel message. He explains that his message predated his own birth, which further supports what he began his letter saying that he was “an apostle not sent from men nor through the agency of man, but through Jesus Christ and God the Father” (Gal. 1:1). Again, in Galatians 1:12, Paul wrote, “I neither received it from man, nor was I taught it, but I received it through a revelation of Jesus Christ.” Paul mentions this event in his mother’s womb to further show that he did not invent the gospel message.
 Guthrie writes, “His point is that this process of setting apart antedates the earliest years of discretion. The calling was in fact before he could think for himself, and this must prove that his gospel was not of his own making.” Guthrie, Donald. Galatians. Grand Rapids: Eerdmans, 1981. 68.