And where is the verse that has him promising this millennial kingdom?
Hello Tom, I would start this response by asking you to explain the kingdom in view here:
Acts 1
King James Version (KJV)
1 The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach,
2 Until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen:
3 To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God:
4 And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me.
5 For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.
6 When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel?
It is unlikely that the "spiritual Kingdom of God" is in view seeing that if we are considering the Church and the introduction of New Covenant promises fulfilled in her, such as the indwelling of God, fulfilled at the coming of the Comforter...then we come into conflict with the kingdom being...restored.
More likely what is in view is that the very kingdom promised which the Disciples at many times indicate by word or action they believe Messiah had come to establish.
In the phrase found here (highlighted)...
7 And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power.
...it seems fairly obvious that two events are in view. We can reasonably conclude that there are two kingdom s in view, one which the Lord will instruct them concerning (v.3), and one that it is not given to the disciples to know at this time.
What will happen, that the Lord
will instruct them concerning, is seen here:
8 But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.
If we consider that there are two Kingdoms, rather than one...one being spiritual and one being an earthly fulfillment of Old Testament prophecy, we can easily reconcile some things that seem unclear.
God bless.