A missionary comes to your church to speak, and you absentmindedly turn to Matt 28:18 or Acts 1:8. Sure enough, this time he will speak about the Great Commission from Acts:
You will receive power when the Holy Spirit has come upon you, and you will be my witnesses in Jerusalem and in all Judea and Samaria, and to the end of the earth.
His sermon touches upon familiar points:
Jerusalem was their home town, and they were supposed to evangelize there first. Judea was their home area. Now, Samaria was like but not identical with Judea, but next in line since it was a nearby mission field. And of course “the end of the earth” means any foreign country. 
In conclusion, the preacher adds:
- We are all called to be missionaries (I take objection to that, by the way, see below).
- What is your Jerusalem and Judea?
- What is your Samaria?
- What is the uttermost part of your earth? Does God want you to preach his gospel in a foreign land?
- You shouldn’t go to the ends of the earth until your Jerusalem is evangelized.
May I propose that we have this all turned around.
First, let’s look at Luke 24. Since Luke and Acts are two volumes by the same author, the last chapter of Luke and the first of Acts overlap. In Luke 24:45-49 Jesus talks about the mission, in different terms and with more detail:
(45) Then he opened their minds to understand the Scriptures, (46) and said to them, “Thus it is written, that the Christ should suffer and on the third day rise from the dead, (47) and that repentance and forgiveness of sins should be proclaimed in his name to all nations, beginning from Jerusalem. (48) You are witnesses of these things. (49) And behold, I am sending the promise of my Father upon you. But stay in the city until you are clothed with power from on high.
Notice the parallels between Luke 24 and Acts 1: Jesus proves himself to be alive; the mission must be preceded by the gift of the Spirit; then the gospel will go forth, specifically from Jerusalem, to all nations. The important new datum from Luke is that this program comes from “the Scriptures” – in other words, the Bible predicted not only the death and resurrection of Jesus; it also foretold that the Spirit would come (as in Joel 2:28-32); and that the gospel would go forth from the city of Jerusalem.
Where did the prophets predict the last part? Most commentators have pointed to Isa 2:3 –
For out of Zion shall go the law, and the word of the Lord from Jerusalem.
The great church father Irenaeus wrote, in Against Heresies 3.20 (ANF 1: 451) –
And again, specifying the place of His advent, he says: “The Lord hath spoken from Zion, and He has uttered His voice from Jerusalem.”
Matthew Henry, in his comments on Ezekiel 47, spoke of Jerusalem and said:
There it was that the Spirit was poured out upon the apostles, and endued them with the gift of tongues, that they might carry these waters to all nations. In the temple first they were to stand and preach the words of this life, Acts 5:20. They must preach the gospel to all nations, but must begin at Jerusalem, Lu. 24:47.
We might add Isa 66:18-19 –
…the time is coming to gather all nations and tongues. And they shall come and shall see my glory, and I will set a sign among them. And from them I will send survivors [in context, the survivors are from Jerusalem] to the nations, to Tarshish, Pul, and Lud, who draw the bow, to Tubal and Javan, to the coastlands far away, that have not heard my fame or seen my glory. And they shall declare my glory among the nations.
The Bible shows that “beginning in Jerusalem” was a once-and-for-all first act in the gospel’s advance: from Zion to whatever nation may be named, God made the gospel go forth by centrifugal force. As Jesus had said in Mark 13:10, before the end of the age “the gospel must first be proclaimed to all nations”; he and the disciples were on the Mount of Olives at the time, facing the Holy City. This also sheds light on Paul’s statement that “from Jerusalem and all the way around to Illyricum I have fulfilled the ministry of the gospel of Christ” (Rom 15:19).
Another observation: until the day of Pentecost, Jerusalem was never the “home town” of the apostles. With the possible exception of Judas Iscariot, the apostles all came from Galilee in the north. Like all Jews they went on pilgrimage to Jerusalem for the Feasts, probably leaving their wives and small children behind. When Jesus was raised, they were staying in a borrowed quarters. Jesus told them to return to Galilee, so that they would see him there (Mark 16:7; Matt 28:10; John 21:1).
So the apostles temporarily returned to their home towns in the north.
They then went back to Jerusalem, moving back to Zion in order to position themselves to go out from Zion in fulfillment of the prophets. 40 days after Easter week, they saw Jesus ascend to heaven. They continued in the city and there receive the Spirit and first preach the gospel. In Acts 2-9 the Twelve are living and working in Jerusalem, their new adoptive town.
Many of the converts on the Day of Pentecost were Diaspora Jews, who later returned from Jerusalem to other nations in their world, taking the gospel to them, from Zion. Due to the persecution, believers moved to Judea and Samaria (Acts 8:1).
From Jerusalem, Phillip went to evangelize Samaria, followed by John and Peter (Acts 8). Peter evangelized the Mediterranean coastline, and made the first gentile convert (Acts 10-11). According to tradition, the apostles then went out to many nations – I just read an old story that may or may not be historically true, about how Andrew was martyred in Patras in southern Greece. 
Samaria was, as we all have been taught, extremely antagonistic to Jews, and the feeling was mutual. But its significance in Acts 1:8 is not simply it was a neighbor to Judea: Samaria had a special part in God’s plan. Although the Israelites in the northern kingdom had intermarried with pagans, still, they were half-Israelites, and worshipers of Yahweh. So like the evangelism of Jerusalem and Judea, this evangelism of Samaria too was unique – it was designed to bring together believers from all the twelve tribes of Israel in Christ.  It is for this same reason that Paul, when he arrived in a new city, made a point to speak first in the synagogue, to give the local Israelites a chance to receive the gospel from Zion – he spoke “to the Jew first” (Rom 1:16).
Back to our fictional preacher from the beginning of our post. While I disagree with his exegesis, still, he makes some valid points:
Application 1. Yes, we must share the gospel wherever we are, in our home town. This is not in order to fulfill the “Jerusalem” mandate of Acts, but still it is a Christian truth: when someone applies to be a missionary, they first must demonstrate that they are practicing the gospel where they live right now. Why go overseas to try to do a thing that you cannot do in your home culture?
Application 2. The first gentile conversion takes place in Caesarea (Acts 10-11), Roman capital of Judea and thus a pagan beachhead in the promised land. So the first mission to gentiles was not in a faraway place, but one in which gentile conquerors had moved in. A similar way to reach “all nations” today is to work with the international students who come to the US to study. The United States is the top destination for foreign students; over a million people came in 2015.  This is a phenomenal opportunity to witness to “all nations,” especially during a time in their lives where they are apart from the pressures of their home culture. Another excellent opportunity is to evangelize those who emigrate to your area from other countries, whether you think they should be your neighbors or not.
Application 3. Not everyone is called to be a missionary, but still everyone of us must be willing to step away from our home culture in order to take the gospel to the world. This is the true definition of a “missionary,” one who is sent from one place to another. All missions agencies are reporting that the number of American missionaries is in steep decline; the baby boomers are retiring, and few young people want to make that sort of commitment. Missionary giving is also falling rapidly, as churches have fewer members, the members are aging, and the churches emphasize short-term mission trips. 
I suppose that there are two errors a church might make. One is to be weak on missions but strong on local evangelism; the other is to be generous with missions “over there” but ignore its own locale. My experience has been that people who are strong in one sphere are also strong in the other. Unfortunately, “concentrating on Jerusalem” sometimes turns out to mean, not local evangelism, but investing in building improvements so that the local lost will be more easily brought into the church building.
Not everyone in our hometown will come to Christ, but we should arrange that they at least hear the gospel. Still, we can and must take the gospel to other cultures and lands before we have our own house entirely in order.
 For examples of this viewpoint, see the article by B. Steve Hughey, “Witnesses…Where? The Four Arenas of Mission Involvement” (https://www.yumpu.com/en/document/view/34919114/witnesses-where-the-four-arenas-of-mission-involvement). Also Jim, Barbarossa, “Have We Forgotten Jerusalem?” (http://www.step-by-step.org/acts1-8.htm)
 Why aren’t they told to evangelize Galilee? One explanation is that Galilee had already been fully evangelized during the earthly ministry of Jesus, in a way that Judea had not been (see Luke 10:1). Another is that the word “Judea” had a variety of meanings. It could mean the southern half of the land, or it could mean all areas in the Holy Land that were inhabited by Jews (it is so used in Luke 23:5), making it include Galilee in Acts 1:8.
 Today there are still Samaritans living in their ancestral land. See http://www.bbc.co.uk/news/world-middle-east-12069728
“From Jerusalem to the Uttermost Parts of the Earth – Have we Misunderstood Acts 1:8?” by Gary Shogren, PhD, Professor of New Testament, San José, Costa Rica