Keep in mind after the 40 days in the wilderness Jesus began to teach that the kingdom of God was at hand and the TIME WAS FULFILLED. Mark 1:15"And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters." Gen 1:2
"The waters are hid as with a stone, and the face of the deep is frozen." Job 38:30
Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: John 16:13
Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you. .John 14:17
And ye also shall bear witness, because ye have been with me from the beginning. John 15:27
And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven. John 3:13
He that cometh from above is above all: he that is of the earth is earthly, and speaketh of the earth: he that cometh from heaven is above all. .John 3:31
But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you. John 14:26
And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him: Matt 3:16
And the Holy Ghost descended in a bodily shape like a dove upon him, and a voice came from heaven, which said, Thou art my beloved Son; in thee I am well pleased. Luke 3:22
(But this spake he of the Spirit, which they that believe on him should receive: for the Holy Ghost was not yet given; John 7:39
What fulfillment of time could Jesus be talking about such a short time after His baptism?
I can think of nothing else except the OT prophecies concerning the coming of the Messiah.