Luke 24:47 and other passages throughout Early Acts have Jerusalem as the focal point of God’s Prophetic aspect of His Two-Fold Purpose: Prophecy and Mystery.
But a Dispensational change has taken place, greatly impacting that. Thus, when Paul goes up to Jerusalem in Galatians 2, some years after his first return to Jerusalem from Damascus, he does not go there for James, Cephas and John's approval of his ministry among the Gentiles, rather, to straighten out a confusion this Dispensational change has resulted in, Gal. 2:7-9.
Question - Years earlier, given the Mystery aspect of God's Two-Fold Purpose where had Paul ended up setting up headquarters, after he first returned to Jerusalem from Damascus and then left for Tarsus, in Acts 9: 26-29?
Answer: “Far hence” from Jerusalem!
In Acts 9:30, Paul, having returned to Jerusalem after his time in Damascus; leaves Jerusalem via Caesarea for Tarsus, some 250 miles away.
Sometime later, in Acts 11: 25-26, we read that Paul travels to Antioch, which is some 86 miles from Tarsus, and about 300 miles from Jerusalem. This is the "far hence unto the Gentiles" he will relate years later.
Not surprisingly, we read there in Acts 11:
25. Then departed Barnabas to Tarsus, for to seek Saul:
26. And when he had found him, he brought him unto Antioch. And it came to pass, that a whole year they assembled themselves with the church, and taught much people. And the disciples were called Christians first in Antioch.
Thus, this “far hence unto the Gentiles” is actually the issue of not only "far hence" from Jerusalem geographically, but spiritually, as well.
Question - when in Acts did the Lord remind Paul he was sending him “far hence unto the Gentiles,” as related by Paul in Acts 22:21?
Carefully contrast Acts 9 with Paul’s account of events in Acts 22 and Acts 26.
What Paul relates in Acts 22:17-21 took place in Acts 9:26-29 (about 37 AD)
While what Paul relates in Acts 26: 14-16 took place earlier in Acts 9:15-17 (about 34 AD).
Both accounts are about events that took place in Acts 9. One within the first three years or so of Paul's conversion and ministry. The other, just after, when he first returned to Jerusalem from Damascus.
In other words, in Acts 9 Paul returns to Jerusalem for the first time after his conversion on the road to Damascus, and ministry (in Damascus).
At this point, Jerusalem has temporarily ceased being what it once was - the very center of spiritual influence unto the entire world, Matt. 5:35; 21:10, 13.
This because Israel has joined the world's rebellion against "the LORD and His Christ, Acts 4: 25-26, and God has concluded Israel under the power of sin with the Gentiles, Rom. 1:18-3:19.
God having foreknown this, had planned to and has, temporarily turned from Jerusalem as His spiritual center of influence, Acts 7:51-53, in light of Matt. 30-32, Rom. 9-11.
The impact of this Dispensational change is once more brought home to Paul when he first leaves Damascus in Acts 9, in about 37 AD, and returns to Jerusalem for the first time (since his conversion on the road to Damascus in about 34 AD).
It is this first return again unto Jerusalem in Acts 9, that he is relating, some 22 years later (about AD 59), in Acts 22:
17. And it came to pass, that, when I was come again to Jerusalem, even while I prayed in the temple, I was in a trance;
18. And saw him saying unto me, Make haste, and get thee quickly out of Jerusalem: for they will not receive thy testimony concerning me.
19. And I said, Lord, they know that I imprisoned and beat in every synagogue them that believed on thee:
20. And when the blood of thy martyr Stephen was shed, I also was standing by, and consenting unto his death, and kept the raiment of them that slew him.
21. And he said unto me, Depart: for I will send thee far hence unto the Gentiles.
(1) Paul gets saved on the road to Damascus, (2) begins his ministry there, (3) then returns to Jerusalem for the first time after his conversion. (4) While in a trance at the Temple in Jerusalem, (5) the Lord appears to him to remind him He has concluded Israel in unbelief; (6) that He is sending him far hence unto the Gentiles. (7) Thus, God's new center of influence under a new Apostle - the Apostle Paul and Antioch.
All one need do is to carefully compare all three accounts – Acts 9, Acts 22, and Acts 26.