'Light' in the Bible

This is the message [of God’s promised revelation] which we have heard from Him and now announce to you, that God is Light [He is holy, His message is truthful, He is perfect in righteousness], and in Him there is no darkness at all [no sin, no wickedness, no imperfection].

but if we [really] walk in the Light [that is, live each and every day in conformity with the precepts of God], as He Himself is in the Light, we have [true, unbroken] fellowship with one another [He with us, and we with Him], and the blood of Jesus His Son cleanses us from all sin [by erasing the stain of sin, keeping us cleansed from sin in all its forms and manifestations].

On the other hand, I am writing a new commandment to you, which is true and realized in Christ and in you, because the darkness [of moral blindness] is clearing away and the true Light [the revelation of God in Christ] is already shining.

The one who says he is in the Light [in consistent fellowship with Christ] and yet habitually hates (works against) his brother [in Christ] is in the darkness until now.

The one who loves and unselfishly seeks the best for his [believing] brother lives in the Light, and in him there is no occasion for stumbling or offense [he does not hurt the cause of Christ or lead others to sin].