Albert Barnes Commentary 1 Timothy 6:16

"who only hath immortality, dwelling in light unapproachable; whom no man hath seen, nor can see: to whom [be] honor and power eternal. Amen." — 1 Timothy 6:16 (ASV)

Who only has immortality. The word here—ayanasia—properly means exemption from death, and seems to mean that God, in His own nature, enjoys a perfect and certain exemption from death. Creatures have immortality only as they derive it from Him, and of course are dependent on Him for it. He has it by His very nature, and it is in His case underived, and He cannot be deprived of it. It is one of the essential attributes of His being that He will always exist and that death cannot reach Him. Compare the expression in John 5:26: The Father has life in Himself.

Dwelling in the light which no man can approach to. Greek: "Inhabiting inapproachable light." The light where He dwells is so brilliant and dazzling that mortal eyes could not endure it.

This is a very common representation of the dwelling-place of God. See examples quoted in Pricaeus, in loc.

Heaven is constantly represented as a place of the most pure and brilliant light, not needing the light of the sun, or the moon, or the stars (Revelation 21:23–24; Revelation 22:5), and God is represented as dwelling in that light, surrounded by amazing and inapproachable glory. Compare Revelation 4:6; Ezekiel 1:4; Hebrews 1:3.

Whom no man has seen nor can see.

To whom be honour and power everlasting. Amen.