God is Light 1 John 1:5
"This is the message we have heard from Him and announce to you, that
God is Light, and in Him there is no darkness at all." 1 John 1:5 NASB
The Gospel of John and his two epistles have two main themes , 1/ God is Light, and 2/ God is Love. My answer will be based on "God is Light" 1 John 1:5
In Him there is no darkness at all, so
"What is Darkness?"
"Darkness" refers to spiritual darkness that has to do with ignorance, senseless, futility, immorality, and wickedness that exist in the realm of Satan, Paul wrote that as the god of this world, Satan ,disguises himself as an angel of light and so has blinded the minds of the unbelieving , so they cannot understand the gospel- the good news.( 2 Cor. 4:4 , 11:14 , Eph.6:12 and John 3:19-21 NASB)
Paul under inspiration by the spirit of God writes that it is the intention of Satan and his demons to keep mankind in spiritual darkness and alienated from the light of God,thus he wrote:
2 Corinthians 4:4 (NASB)
4 " In whose case the god of this world has blinded the minds of the
unbelieving so that they might not see the light of the gospel of the
glory of Christ, who is the image of God."
2 Corinthians 11:14 (NASB)
14 "No wonder, for even Satan disguises himself as an angel of light."
Paul helps us by the contrast in the following verse we have a serious fight, the fight is not against mere man but against Satan and his spiritual demons.
Ephesians 6:12 (NASB)
12 "For our struggle is not against flesh and blood, but against the
rulers, against the powers, against the world forces of this darkness,
against the spiritual forces of wickedness in the heavenly places."
John 3:19-21 (NASB)
19 "This is the judgment, that the Light has come into the world, and
men loved the darkness rather than the Light, for their deeds were
evil. 20 For everyone who does evil hates the Light, and does not come
to the Light for fear that his deeds will be exposed. 21 But he who
practices the truth comes to the Light, so that his deeds may be
manifested as having been wrought in God.”
What is Light
Light in the sense of Spiritual Light, has to do with the knowledge, and spiritual enlightenment that comes from studying the Bible, God's Word
2 Corinthians 4:6 (NASB)
6 "For God, who said, “Light shall shine out of darkness,” is the One
who has shone in our hearts to give the Light of the knowledge of the
glory of God in the face of Christ."
Revelation 22:5 (NASB)
5" And there will no longer be any night; and they will not have need
of the light of a lamp nor the light of the sun, because the Lord God
will illumine them; and they will reign forever and ever."
God Is Light.
God is Light, and in Him there is no darkness at all - God is holy , is pure and no evil is to be found in him , hates wickedness and immorality and is the God of Truth ( Titus 1:2 ,Rev. 4:8, Habakkuk 1:14)