When David undertook to go into the valley of Elah, and fight Goliath the champion of the Philistine army, Saul arrayed him with his own armour. But the young shepherd felt uncomfortable in the royal coat of mail and the helmet of brass belonging to the tallest man in Israel. Wisely he chose to go in the simple unpretentious way in which God had blessed him when he met the lion and the bear. Those who fight in God's battles must do so obediently to His regulations, and ignore the good-natured suggestions of worldly-minded people.
In the New Testament we do not read of coats of mail and helmets of brass, nor even of slings and stones, for the use of the children of God. But the apostle wrote to the Roman believers, "Let us therefore cast off the works of darkness, and let us put on the armour of light" (Rom. 13:12). The armour of light is not material, but moral and spiritual, and suitable for those who are children of the light and who walk in the light.
Please observe in the first place that there is something for you to do in connection with this protective covering: you must put on this armour. If another clothes you with some substitute, it will not fit you, and you will be hampered in the fray. You must wear the approved armour: you must cast off the works of darkness, and put on the armour of light.
Now the Lord Jesus is the Light of the world, and the armour of light is associated with the character which He bore in this world. The Fourth Gospel speaks a great deal of Him as the Light of life. His words were light, and His works were light. It is therefore through the record of our Lord Jesus given us in the scriptures that we learn what is light, and so discover what is the armour of light which we are exhorted to put on.
The Lord never had to put on this armour, because He was in Himself light. But we were once darkness, though now we are light in the Lord (Eph. 5:8). Therefore we must put off the works of darkness, and put on the armour of light. Each believer is responsible to provide himself with this protective covering.
No doubt you are at this point ready to ask the question, What are we to understand by the expression, "the armour of light?" A great deal might be written upon this topic, but I will try to give a general answer in a few words. And I will do so by first referring to the Lord Jesus as an example, and then by referring to one of the apostles as a contrast to Him. You will then, I hope, be able to gather what is the practical meaning of the phrase.
In the Old Testament we read of God as the One Who covers Himself "with light as with a garment" (Ps. 104:2). This might be said of our Lord as He walked through this world of darkness. There was a perfect contrast between Him and all who were around Him. This was true of Him throughout the years of His ministry, but is particularly noticeable in the hours immediately preceding His crucifixion.
Let me remind you of the terrible scene which commenced in the garden of Gethsemane. The Lord then said to those who came to apprehend Him, "This is your hour and the power of darkness" (Luke 22:53). They had come out with their swords and staves to do deeds of darkness. But the Lord was serene and unaffected in the face of their threatenings and weapons. Neither He nor His servants would fight carnally, for His kingdom was not of this world of darkness.
And yet His enemies saw the light of His presence, the light which was not of this world; for when He said to them, I AM, they went backward and fell to the ground (John 18:6), In spite of their hatred of Him, they recognised that He was infinitely greater and higher and holier than they. There were no physical weapons, no sword, no spear, no sling, no stone, but there had been an hour's watching and prayer in the garden. The light of the Father's presence lingered on the face of Jesus of Nazareth, and evil-minded men were confounded and overcome by the glory of that light.
I suggest that you meditate upon the meekness and calmness of the Lord before Caiaphas and Annas, Pilate and Herod, among the soldiers and the mob, bearing the cross and borne up on the cross, that you may learn how the Light shone in the darkness, and the darkness comprehended it not. This meek submission is the armour we are called to wear; as Peter wrote, "Forasmuch as Christ hath suffered for us in the flesh, arm yourselves likewise with the same mind" (1 Peter 4:1).
But I will now ask you to think of one who affords a striking contrast with the Lord Jesus on that night when He was betrayed. I refer, of course, to the apostle Peter. He first of all drew his sword and smote off the ear of Malchus in defence of his Master. But the Lord rebuked him because he was using the wrong weapons. He was resisting evil in a carnal fashion, forgetting that the Lord's kingdom was not of this world, else His servants would fight as is the way of the world.
Further this error of Peter's was followed by another, more serious. When he went into the courtyard of the High Priest, he mingled with the servants as one of themselves. And when he was challenged as a disciple of Jesus of Nazareth, he was carried away by the fear of man and denied it with oaths and curses. Thus, we have the humiliating spectacle of the great apostle arrayed in works of darkness instead of the armour of light. One of the maidservants thought she saw the glitter of the shining armour, and said to him, "Art not thou also one of this Man's disciples?" But Peter cast off the armour of light, put on the works of darkness, and deliberately and emphatically declared, I am not.
There was therefore a striking contrast between Simon Peter and the Lord Jesus who endured "the contradiction of sinners against Himself," and was perfect in His demeanour of meekness and gentleness and submission. The reason for the disciple's failure was that he failed to watch and pray in the garden of Gethsemane, as the Lord enjoined (Mark 14:37, 38). Simon slept, instead of watching. Those who are about to sleep do not put on armour for the purpose, To arm ourselves involves alertness and vigilance, the watchful attitude.
But there was also prayer. The Lord prayed on three distinct occasions in Gethsemane, and then He went forth, strong to meet His foes. Here then is the secret. We must follow the Lord into the place of prayer in order to stand for Him in the place of testimony. When the Lord was alone praying on the mountain, the glory-light shone in His face. Those who come out of the prayer-closet will be clothed with the armour of light.
By comparing verse 14 with Rom. 14:12, you will see that putting on the armour of light is synonymous with putting on the Lord Jesus Christ. Those who walk like Him, pray like Him, work like Him, speak like Him, love like Him, are the ones who wear this wonderful covering, and are not overcome by the powers of darkness. Let us therefore seek to be strong in the grace that is in Christ Jesus, and to be equipped to meet all the assaults of the world and Satan its prince.