2Cor 3-5
In the OT, the glory of God was the bright light that surrounded the presence of God. It led the Israelites out of Egypt as a pillar of cloud by day and a pillar of fire at night (Ex 13:21-22). Later, it filled the tabernacle under Moses (Ex 33:8-13); then it filled Solomon's temple (1Ki 8:10-11). Then the Glory departed Israel during their exile to Babylon due to their sins (Ezek 10:4, 18-19; 11:23). But it returned to Israel with Jesus' first advent (Jn 1:14), thereby supplanting and eclipsing the Shekinah Glory of the second temple, since Christ is the antitype to the OC temples (Jn 2:19); and this Glory will shine forever "in the face of Jesus" which stands in sharp contrast to Moses whose glory faded away from his face (2Cor 3:13).
Further, we have Paul's conversion in Acts 9 which is emblematic of everyone's spiritual conversion; for each of us who are truly born again have had our own version of Paul's On-the-Road-to-Damascus conversion experience, whether that experience was spectacular like Paul's or more or less "ordinary". God in his infinite wisdom knows how to deal with each of us according to our personalities and the conditions of our hearts. It's noteworthy, however, that Paul's conversion occurred after God sent his servant Ananias to heal the apostle's blindness.
Finally, Paul draws an analogy between the creation of Light in this physical world (Gen 1:3-5) and the spiritual New Creation whereby God shines his Light into his people's hearts to dispel the darkness,which epitomizes the very essence of unregenerate sinners; and He does this so that they may become children of Light (Eph 5:8). This metaphor should not be glossed over or dismissed. For just as this physical world would not be able to produce life or sustain itself apart from Light which produces life, neither could there be a new creation apart from God shining the Light of Life (Jn 8:12) into dead, depraved, darkened minds and hearts. Paul himself ties in this creation language into the New Creation (2Cor 5:17).
Mr. Studier recently argued that 2Cor 4:6 was basically a one-time unique event with Paul (and maybe with other apostles?), and that God's efficacious work in shining his light into hearts was temporary and ended after the first century. However, there is nothing in this epistle that even remotely suggests that God's work has an expiration date on it. While I agree with Studier that Paul is alluding to a supernatural work that was done in him (very likely his Damascus Road experience), this alone does not translate into a one-time supernatural act or an act restricted to a particular time period. So, against the backdrop of my opening three paragraphs, what follows are my reasons why.
1. The eternal New Covenant has no expiration date on it (3:11), whereas the Old did, which of course is one of the big distinctions between the two. And the supernatural act Paul describes in chapter 4 occurred in and applies to this NC economy, and is consistent with the unconditional, unilateral promises of this covenant as revealed in Jer 31-32, Ezek 36, etc.
2. While it is true that God's supernatural work in Paul, Timothy and Silas (1:19) empowered them (4:7) to preach the Gospel with confidence, conviction, clarity, zeal and love, this doesn't mean that that work was restricted to just them or to others in only the first century. Quite to the contrary! Since two "ordinary" (non-apostolic) believers also shared in this specific, supernatural experience of grace (likely as part of their conversion experience), there is no compelling reason to believe that others didn't and aren't currently experiencing the same grace of God today. Moreover, we should bear in mind that Paul broaches this whole subject in the personal context of him defending his calling from God to the office of apostleship, generally, and his call to minister to the Corinthians more specifically. He contrasted himself with phony apostles, preachers and teachers, who unlike Paul, Timothy and Silas, were not so empowered by God (4:7).
3. Paul was made a minister of the New Covenant. But was he the only or last minister of the eternal NC? Are we to believe the Church has been bereft of any such ministers for nearly 2,000 years now? Pastors, teachers, evangelists, missionaries and and all other kinds of Christians are not ministers of the NC today? Was God's inner revelation of his Glory during this NC era also temporary the way it was under the OC? Yet, Paul taught that the glory of the NC is permanent (3:11). If God's glory was manifested in brick 'n' mortal OC temples (a mere type), it's no longer manifested in the antitype, i.e. his true, eternal, spiritual temple who is Christ and in his Body which are living stones to that temple (1Pet 2:5)? Christians today are no longer ambassadors of Christ (5:20), or aren't involved in any ministry of reconciliation whenever they preach or share the gospel with anyone (5:18-19)?
4. Since God deemed it necessary to shine the light of his glory by his Spirit into the hearts of Paul, Timothy and Silas during their conversion, then how did it become unnecessary for any of God's elect throughout this NC age to receive this grace? Do unbelievers today have better hearts than their first century counterparts? Or is Satan no longer blinding the minds of unbelievers to keep them in the dark? Is the devil no longer holding the world captive to do his will (1Jn 5:19)? Is there no more veil to be lifted in Christ (3:14, 16)? The world today doesn't have to concern itself with such a veil? It was Paul who completed Christ's work of destroying the works of the devil (1Jn 3:8), making it unnecessary for any believer or unbeliever today to be concerned about the wiles and schemes of Satan?
5. Paul, in hearkening back to his old/new creation analogy (4:6) told the Corinthians that if anyone is in Christ, he is a "new creation" (5:17). To deny that 4:6 is as applicable today to Christians as it was in Paul's day is tantamount to denying that modern Christians have been so thoroughly transformed into the image of the Lord (3:18) that they could indeed be called God's "new creation". The old things have passed away; all things have become new; for all Christians were once Darkness in their very essence but are now children of Light due to God's powerful, efficacious work of shining his Light into their hearts. This fact accounts for how Christians are God's New Creation! Therefore, the Light which God shines into the hearts of his people is as critically essential to spiritual life and the transformation which flows therefrom, as was the light that God called into his physical creation to produce, support and sustain physical life. Where there is no Light, there is no Life in either of these two realities!
6. Lastly, if 4:6 was just an anomaly peculiar to the first century, then the Gospel is not truly being preached today since God put that "word of reconciliation" (5:19) only into the hearts of Paul, Timothy and Silas. Therefore, just what kind of Gospel is being preached and taught today if not the "word of reconciliation" to a lost world?
While it is is very convenient and easy to dismiss 2Cor 4:6 as but a work of God that only applied to Paul, and I suppose other first century believers, as well, nonetheless very serious theological issues arise for those who want to posit the temporary or transitory nature of the supernatural, efficacious phenomenon that occurred in this New Covenant dispensation, since all God's spiritual work in this age is permanent and in fact will be culminated in the New Order at the Parousia.