This promise does not involve that the Apostles, and through them all disciples, should know everything. “All the truth” is relative to the subject taught. All that they need to know regarding Christ and His work for them they will learn. All that is needed to glorify Christ, to enable men to recognise Him as the manifestation of God, will be imparted. To the truth which the Apostles learn, therefore, nothing need be added. Nothing essential has been added. Time has now been given to test this promise, and what time has shown is this—that while libraries have been written on what the Apostles thought and taught, their teaching remains as the sufficient guide into all the truth regarding Christ. Even in non-essentials it is marvellous how little has been added. Many corrections of misapprehensions of their meaning have been required, much laborious inquiry to ascertain precisely what they meant, much elaborate inference and many buildings upon their foundations; but in their teaching there remain a freshness and a living force which survive all else that has been written upon Christ and His religion. This instruction of the Apostles by the Spirit was to recall to their minds what Christ Himself had said, and was also to show them things to come. The changed point of view introduced by the dispensation of the Spirit and the abolition of earthly hopes would cause many of the sayings of Jesus which they had disregarded and considered unintelligible to spring into high relief and ray out significance, while the future also would shape itself quite differently in their conception. And the Teacher who should superintend and inspire this altered attitude of mind is the Spirit.[19] Not only must the Spirit enlighten the Apostles; He must also convince the world. “He shall bear witness of Me,” and by His witness-bearing the testimony of the Apostles would become efficacious. They had a natural fitness to witness about Christ, “because they had been with Him from the beginning.” No more trustworthy witnesses regarding what Christ had said or done or been could be called than those men with whom He had lived on terms of intimacy. No men could more certainly testify to the identity of the risen Lord. But the significance of the facts they spoke of could best be taught by the Spirit. The very fact of the Spirit’s presence was the greatest evidence that the Lord had risen and was using “all power in heaven” in behalf of men. And possibly it was to this Peter referred when he said: “We are His witnesses of these things; and so is also the Holy Ghost, whom God hath given to them that obey Him.” Certainly the gifts of the Holy Ghost, the power to speak with tongues or to work miracles of healing, were accepted by the primitive Church as a seal of the Apostolic word and as the appropriate evidence of the power of the risen Christ.