He did so in part on the Mountain with the Apostles
Luke 9:27 But I tell you of a truth, there be some standing here, which shall not taste of death, till they see the kingdom of God.”
Matthew 16:28 Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.”
And also through his resurrection from the dead:
Daniel 7:13-14 I saw in the night visions, and, behold, one like the Son of man came with the clouds of heaven, and came to the Ancient of days, and they brought him near before him.”And there was given him dominion, and glory, and a kingdom, that all people, nations, and languages, should serve him: his dominion is an everlasting dominion, which shall not pass away, and his kingdom that which shall not be destroyed.”
Acts 1:9 And when he had spoken these things, while they beheld, he was taken up; and a cloud received him out of their sight.”
Ephesians 1:20-21 Which he wrought in Christ, when he raised him from the dead, and set him at his own right hand in the heavenly places,”Far above all principality, and power, and might, and dominion, and every name that is named, not only in this world, but also in that which is to come:”And hath put all things under his feet, and gave him to be the head over all things to the church,”