They wanted power, and He assured them that they should have it, but said nothing of its nature, or the work and activities into which it would thrust them, and for which it would equip them, beyond the fact that they should be witnesses unto Him "in Jerusalem and Samaria, and unto the uttermost parts of the earth." After that the Holy Ghost Himself was henceforth to be their Teacher. And then Jesus left them. Earth lost its power to hold Him, and while they beheld Him He began to ascend; a cloud bent low from Heaven, receiving Him out of sight, and they were left alone, with His promise of power ringing in their ears, and His command to "wait for the promise of the Father" checking any impatience that might lead them to "go a-fishing," as Peter had done some days before, or cause an undue haste to begin their life-work of witnessing for Him before God's appointed time. For ten days they waited, not listlessly, but eagerly, as a maid for her mistress, or a servant for his master, who is expected to come at any moment; they forgot their personal ambitions; they ceased to judge and criticise one another, and in the sweet unity of brotherly love, "with one accord" they rejoiced, they prayed, they waited; and then on the day of Pentecost, at their early morning prayer meeting, when they were all present, the windows of Heaven were opened, and such a blessing as they could not contain was poured out upon them. "And suddenly there came a sound from Heaven as of a rushing mighty wind, and it filled all the house where they were sitting. And there appeared unto them cloven tongues like as of fire, and it sat upon each of them. And they were all filled with the Holy Ghost." This was the inaugural day of the Church of God: the dawn of the dispensation of the Holy Spirit; the beginning of the days of power. In the morning of that day there were only a few Christians in the world; the New Testament was not written, and it is doubtful if they had among them all a copy of the Old Testament; they had no church buildings, no colleges, no religious books and papers; they were poor and despised, unlearned and ignorant; but before night they had enrolled three thousand converts from among those who, a few weeks before, had crucified their Lord, and they had aroused and filled all Jerusalem with questionings and amazement. What was the secret? Power. What was the secret? God the Holy Ghost. He had come, and this work was His work, and they were His instruments.