Why did Jesus tell the demons to be quiet/silent about who He was?

But He did not only teach, that day; for a man was there with an unclean spirit, as Mark states — a demon, as Luke calls it. If the congregation listened to the Lord in silence, struck by His teaching, that man could not keep quiet. He attracted the Lord's attention by speaking to Him in a language all could understand — the language of man, yet giving utterance to the thoughts of the demon within him: "What have we to do with Thee, Thou Jesus the Nazarene? Art Thou come to destroy us? I know Thee who Thou art, the Holy One of God" (1:24). The demon would bear testimony to the Lord; but the Lord would not receive it. What that spirit made its victim utter was all true. The Nazarene was the Holy One of God, and He will deal in judicial and almighty power with that spirit in a future day. Testimony, however, from such a source He would not accept; so He rebuked the demon, saying, "Hold thy peace, and come out of him" (ver. 25). The unclean spirit obeyed, and came out, having first torn the man, and having cried with a loud voice. Demoniacal possession is a reality. There was no illusion. That spirit's power was displayed, and its voice heard; but the power of the Lord was greater. And however unwilling to leave its victim, at the word of Christ, "Hold thy peace, and come out of him," it came out.

Though Israel did not know the Messiah, the demons were inwardly conscious of the personality of this Servant of Jehovah, and would have declared it aloud. This the Lord forbade, as in the synagogue. He did accept the fourfold witness of the Baptist, the Father, His own works, and the Scriptures (John 5:32-47), but He, the Holy One of God, disclaimed all testimony from beneath. In that wisdom which He possessed so perfectly as a Man, He, anticipating the unfounded charge against Him of complicity with Beelzebub in the expulsion of demons, and to give no occasion of stumbling to any of the Father's "little ones," publicly renounced all association with the works of darkness, so that all might know that these things were wrought by Him in His Father's name alone.

40, 41. "And having laid his hands on every one of them, he healed them." Satan, when he could not oppose, and constrained to recognise the actual power as of the Son of God and His Kingdom, would have share, nay, take the lead in recognising it, that it might be accredited by him, and so he retain his paramount influence as far as possible over the minds of men, and credit, and station in the world, and make God, as it were, a debtor to him for his sanction in it. So with Paul at Philippi, but not so the Spirit of God; He works His own holy purpose, and separates, by the reception or rejection of His own testimony, those who love or hate the light. And it is only in presenting Christ in this moral character of trial that His work is truly wrought. The spirits knew it, and the master spirit would have made use of this knowledge to minister subtle hindrance to the Lord's kingdom, and maintain, as we have seen, his influence over the blinded heart of man, but the Lord "suffered them not to speak."

Not only did He heal men of divers diseases, He also delivered them from the power of demons. But while manifesting His complete power over demons, He "suffered not the demons to speak because they knew Him". As one has said, "He refused a testimony that was not of God. It might be true, but He would not accept the testimony of the enemy."

Who was upon Earth? — The Lord had determinedly refused the testimony of demons to Himself, true though it was (Luke 4:35, 41). For how could the Holy One of God receive testimony from such creatures? Nor were men to be indebted for their knowledge about Him to that which a demon might declare. So Luke goes on to show Theophilus how truth as to His person was brought out. His acts and His words proclaimed, and that in a threefold manner, who He was, viz., the Creator, Jehovah, and the Son of Man.

To avoid the crowds He asked His disciples to provide a small boat for Him. It is not here said that He preached from the boat (as in ch.4:1-2), but that because of His healing many, the crowd more intensely pressed upon Him, those specially anxious who had infirmities. Those with unclean spirits were drawn also by the crowds, and crying out that He was the Son of God. Though this was true, yet the Lord did not want the witness of evil spirits, nor was He there to display the greatness of His gory, but in serving mankind, He sought to draw the attention to the Word of God, that men should obey it. Their witness only caused excitement rather than sober exercise of heart and conscience. Therefore He silenced them.

Thus Jesus the Son of God was the bruiser of Satan, as before He had been his binder and his spoiler. But there is another moral glory that is seen to shine in the ministry of Christ, in the relation it bears to Satan. I mean this: He never allows him to bear witness to him. The testimony may be true, and, as we say, flattering, good words and fair words, such as, "I know thee who thou art, the holy One of God," but Jesus suffered him not to speak. For His ministry was as pure as it was gracious. He would not be helped in His ministry by that which He came to destroy. He could have no fellowship with darkness, in His service, any more than in His nature. He could not act on expediency, therefore rebuke and silencing of him was the answer he got to his testimony. As far as the Lord's ministry in the Gospel goes in relation to Satan, He is simply, as we have now seen, his binder, his spoiler, his bruiser. In the Apocalypse, we follow Him in further relations to the same adversary. There we see Him "casting him down from heaven;" then, in due season, "putting him in the bottomless pit;" and afterwards leaving him in "the lake that burneth with fire and brimstone." [Rev. 12 & Rev. 20 We thus track His conquest over him, from the wilderness of the temptation to the lake of fire.] Then as to man, the moral glories which show themselves in the ministry of the Lord Jesus, are bright and excellent indeed.

Thus, then, the ministry of the Lord Jesus Christ is fully come. It is thus that he enters upon it in Mark. It is clearly the manifestation of the truth of God with authority. Divine power is vested in man over the devil, as well as over disease. Such was the form of the ministry of Jesus. There was a fulness in it naturally, one need scarce say, which was suitable to Him who was the head of ministry as well as its great pattern here below, no less than, as He is now, its source from His place of glory in heaven. But there is another notable feature in it, too, as contributing to fill this instructive introductory picture of our Lord's ministry in its actual exercise. Our Lord "suffered not the devils to speak, because they knew Him." He refused a testimony that was not of God. It might be true, but He would not accept the testimony of the enemy.

But "Jesus rebuked him," refusing a demon's testimony; as the apostle did at a later day. God testifies by His word, as He was then testifying in Jesus, His Son and Servant; and the Holy Spirit is now sent forth to bear witness of Jesus, that you may believe on Him and be saved.

But, His hour not being yet come, Jesus withdrew with His disciples to the sea, retiring from the hypocritical malice of His enemies, but unwearied on the errand of love on which He was sent. "And a great multitude from Galilee followed Him, and from Judea, and from Jerusalem,37 and from Idumea, and from beyond Jordan; and they about Tyre and Sidon, a great multitude, when they had heard what great things He did, came to Him. And He spake to His disciples that a small ship should wait on Him because of the crowd, lest they should press upon Him. For He healed many; so that they beset Him, that they might touch Him, as many as had plagues." After all, how little can man arrest the stream of blessing! Till God's time arrives to yield to the cross the stream of testimony may be diverted, but it will flow to the eternal joy of the poor and needy who bow to Jesus. In the cross it overflowed. But the Lord, intent on the best blessings for man, provides against the overpressure of a crowd too engrossed in the relief of bodily weakness and suffering; while He refuses the testimony of the unclean spirits, compelled to bow and own His glory. It was not for such to make Him known. He received not testimony from man as such, much less from demons.38 What was the value of any recognition of His person unless it were of God's own working by the Spirit?