Verse 8: The True Light Shining
Yet I am writing you a new command; its truth is seen in him and in you, because the darkness is passing and the true light is already shining.
This commandment was not new because its seed had already been planted in the Old Testament, but because of the weakness of human flesh it was never fulfilled, and therefore, the commandment was new because it could now be carried out by those who walk in Christ by the Holy Spirit:
Romans 8:3-4 (CSB) What the law could not do since it was weakened by the flesh, God did. He condemned sin in the flesh by sending his own Son in the likeness of sinful flesh as a sin offering, 4 in order that the law’s requirement would be fulfilled in us who do not walk according to the flesh but according to the Spirit.
“Its truth is seen in him”: the whole world was brought under the yoke of corruption and every soul was slave to sin and death, but Christ came at just the right time, emptying himself of his rightful privileges and taking on himself our human mortality, he accomplished in the flesh what no mortal had ever done before when he perfectly shed the light of God’s love into the world and made himself an atoning sacrifice for our sins on the cross.
“And in you”: what we have never been able to do before because of the weakness of our humanity is now possible through our unrestricted fellowship with the presence of God himself:
Galatians 5:6 (CSB) For in Christ Jesus neither circumcision nor uncircumcision accomplishes anything; what matters is faith working through love.
Galatians 5:16, 22-25 (CSB) I say then, walk by the Spirit and you will certainly not carry out the desire of the flesh. 22 But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, 23 gentleness, and self-control. The law is not against such things. 24 Now those who belong to Christ Jesus have crucified the flesh with its passions and desires. 25 If we live by the Spirit, let us also keep in step with the Spirit.
The righteous requirement of the law has always been faith expressed through love (Rom. 13:10), but the flesh has always been blind towards faith and has never been strong enough for love. But now we have the advantage of the Holy Spirit, and those who walk in the Spirit by faith carry out the righteous commandment of the Law (love).
“Because the darkness is passing”: the heavy veil that has blinded our eyes is passing away because of Christ:
John 1:4-5, 9 (CSB) In him was life, and that life was the light of men. 5 That light shines in the darkness, and yet the darkness did not overcome it. 9 The true light that gives light to everyone was coming into the world.
John 8:12 (CSB) Jesus spoke to them again: “I am the light of the world. Anyone who follows me will never walk in the darkness but will have the light of life.”
“And the true light is already shinning”: the light of life is the love of God in Christ Jesus, whose light God has shed into our hearts:
2nd Corinthians 4:6 (CSB) For God who said, “Let light shine out of darkness,” has shone in our hearts to give the light of the knowledge of God’s glory in the face of Jesus Christ.
The darkness is not yet passing away from the carnal world, but rather, is being driven from our hearts by the shining face of Jesus Christ who lives and abides in us. Because of this we see that it is impossible for those who have the light of Christ abiding in them to live in the darkness.
Biblical Reasons 