in whom the god of this world has blinded the thoughts of the unbelieving, so that the radiancy of the glad tidings of the glory of the Christ, who is [the] image of God, should not shine forth a [for them].
I add 'for them' to complete the sense. I have doubted as to this passage. The word translated 'shine forth' is only found here in the New Testament and generally means 'to see,' or 'discern.' If this be the meaning here, we should read 'so that they should not discern the shining forth of the glad tidings of the glory of Christ, who is the image of God.'