Jamieson, Fausset and Brown on 2 Corinthians 4:6

6. For--proof that we are true servants of Jesus unto you.

commanded the light--Greek, "By speaking the word, commanded light" (Ge 1:3).

hath shined--rather, as Greek, "is He who shined." (It is God) who commanded light, &c., that shined, &c., (Job 37:15): Himself our Light and Sun, as well as the Creator of light (Mal 4:2; Joh 8:12). The physical world answers to the spiritual.

in our hearts--in themselves dark.

to give the light--that is, to propagate to others the light, &c., which is in us (compare Note, see on 2Co 4:4).

the glory of God--answering to "the glory of Christ" (see on 2Co 4:4).

in the face of Jesus Christ--Some of the oldest manuscripts retain "Jesus." Others omit it. Christ is the manifestation of the glory of God, as His image (Joh 14:9). The allusion is still to the brightness on Moses' "face." The only true and full manifestation of God's brightness and glory is "in the face of Jesus" (He 1:3).