The subject of light pervades the Scriptures. Spiritual and moral light come first; physical light was created afterwards as a picture of what is spiritual and moral. Thus God is light (1 John 1:5); Christ is the light (John 8:12); the Lamb is the light (Rev. 21:23); the Word of God is light (Psalm 119:105); local assemblies are the light of testimony (Rev. 1:12); the Lord's people are light (Matt. 5:14); the gospel is light (2 Corinthians 4:4); the path of the just is light (Prov. 4:18).

—What the Bible Teaches, Vol. 6