3:18 we all. All Christians. A characteristic experience of new covenant believers is described here.

beholding. Unlike Moses (v. 13), who went before the people with a veil to hide the fading glory on his face, Paul stands before people “with unveiled face,” knowing that the new covenant glory will never diminish. Likewise “we all” stand unashamedly before the world, reflecting in our own lives the glory of Christ. And far from a fading glory, our glory is ever-increasing, as we are changed more and more into the likeness of Christ. See “The Transfiguration of Jesus” at Mark 9:2.

into the same image. A reference to continual growth throughout life into increasing Christlikeness. This growth is moral and spiritual transformation “from one degree of glory to another.” We are being progressively restored to greater and greater possession of the image of God which was corrupted at the fall of Adam.