In saying that Jesus “has shown on our hearts,” he is including Christians other than himself, including Timothy etc.1 This is relevant because, Paul felt Jesus appeared to him “last of all.”2 To be clear,…
• Daniel Kendall & Gerald O'Collins: “The language of light in 2 Cor 4:6 refers to the general Christian experience of conversion, not to Paul's particular experience on the road to Damascus.” [“The Uniqueness of the Easter Appearances,” Catholic Biblical Quarterly 54:2 (1992): 291.]
• N.T. Wright: “Paul does not imagine that every time the gospel is preached, people see the lord in the same way that he did on the road to Damascus.” That is to say, while Paul claims to have converted as a result of Jesus’ appearing to him alive from the dead, Timothy (who he writes to) was not converted through an appearance, nor did others who Paul refers to in saying ‘our.’” [The Resurrection of the Son of God (Fortress, 2003), 385.]
Contextually, what Paul is saying “shone in our hearts” is the gospel; i.e. Paul is referring to the faith-perceived luminosity given off by the life-transforming good news.
• Context topic: “light of the gospel” v4 (vs. “blinding” caused by Satan).1
• Paul: “All Christians experience this. (See above.)
Rather than being some soft warm shining or inner illumination in Paul’s heart (leading to conversion), Paul’s encountering Christ was a violently disruptive experience.
• It’s predictable—a mere warm feeling couldn’t convert Paul.
• 1 Cor 15 — “as to one untimely born”
According to Acts, when Jesus appeared to Paul on the road to Damascus, there was an experience of light.
• Acts 22:6-8 — “a very bright light.”
• Acts 26:13-15 — “ I saw on the way a light.”
• Gerd Lüdemann: “[2 Corinthians 4:6 is] a possible reflection of the Damascus event… [which would explain why it] ‘had the character of light’ [Resurrection of Jesus (Prometheus, 2004), 53, 163].
But no...
• Commentators rather identify the “light” as the light of the Gospel.1
But so what?
• This argument depends on the credibility of Acts, which says Paul is loud in reporting that this light physically impacted his companions in several ways.
Paul writes, “For God, who said, ‘Light shall shine out of darkness,’ is the one who has shown in our hearts to give the Light of the knowledge of the glory of God in the face of Christ.”
This is relevant because according to Acts, Jesus’ appearance to Paul was associated with light (see above), and inevitably this involved Jesus’ face shining with God’s glory.
But no…
• This is not the Damascus light. Paul’s discussion of “faces” links to 3:12-18 (“faces.. veiled.. unveiled”).
But so what?
• This argument depends on the credibility of Acts, which says Paul is loud in reporting that this light physically impacted his companions in several ways.