Tertullian

"But when the fulness of time was come, God sent forth His Son"-the God, of course, who is the Lord of that very succession of times which constitutes an age; who also ordained, as "signs" of time, suns and moons and constellations and stars; who furthermore both predetermined and predicted that the revelation of His Son should be postponed to the end of the times. "It shall come to pass in the last days, that the mountain (of the house) of the Lord shall be manifested"; "and in the last days I will pour out of my Spirit upon all flesh" as Joel says. It was characteristic of Him (only) to wait patiently for the fulness of time, to whom belonged the end of time no less than the beginning. But as for that idle god, who has neither any work nor any prophecy, nor accordingly any time, to show for himself, what has he ever done to bring about the fulness of time, or to wait patiently its completion? If nothing, what an impotent state to have to wait for the Creator's time, in servility to the Creator! But for what end did He send His Son? "To redeem them that were under the law," in other words, to "make the crooked ways straight, and the rough places smooth," as Isaiah says-in order that old things might pass away, and a new course begin, even "the new law out of Zion, and the word of the Lord from Jerusalem," and "that we might receive the adoption of sons," that is, the Gentiles, who once were not sons. For He is to be "the light of the Gentiles," and "in His name shall the Gentiles trust." That we may have, therefore the assurance that we are the children of God, "He hath sent forth His Spirit into our hearts, crying, Abba, Father." For "in the last days," saith He, "I will pour out of my Spirit upon all flesh."

" Now was absolutely fulfilled that promise of the Spirit which was given by the word of Joel: "In the last days will I pour out of my Spirit upon all flesh, and their sons and their daughters shall prophesy; and upon my servants and upon my handmaids will I pour out of my Spirit." Since, then, the Creator promised the gift of His Spirit in the latter days; and since Christ has in these last days appeared as the dispenser of spiritual gifts (as the apostle says, "When the fulness of the time was come, God sent forth His Son; " and again, "This I say, brethren, that the time is short" ), it evidently follows in connection with this prediction of the last days, that this gift of the Spirit belongs to Him who is the Christ of the predicters.