In a previous post, I provide some background about Samaria that relates her to Israel, the northern kingdom (2 Kings 17:24). According to the end of 2 Kings 17, it appears that Samaria is destined to repeat the sins of Israel over and over again. What about the exiles that the Assyrians carried off when they conquered Samaria in 722 B.C.? Notice that the Old Testament never records a return for these exiles. The returning exiles of Ezra and Nehemiah are much later exiles. Their exile and return has to do with the Babylonian conquest of Jerusalem and Judah.
Based on the Old Testament, it appears that the story of Samaria somehow continues the story of the northern kingdom, Israel. We know that people in Samaria continue to worship God, because they build a temple on Mount Gerizim, which a Judean king (John Hyrcanus) destroys around 128 B.C. They also have their own version of the Pentateuch (the Samaritan Pentateuch). In the New Testament, Samaria becomes the name for the region in which the Samaritans live.
This is where the words of the Old Testament prophets become important. They predict a future for the northern kingdom. Part of that future involves reuniting with the southern kingdom of Judah under one king. A prominent example of such a prediction occurs in Ezekiel 37:15-28. God will reunite Israel and Judah into one kingdom with one king (37:19, 22). They will no longer worship idols (37:23). One king, a new David, will rule over them so that they will have “one shepherd” and obey the Lord, their God (37:24).
So, then, in Acts 1:8 and 8:4-24, the conversion of the Samaritans to faith in Jesus, the son of David, is a significant indicator that God’s words to Ezekiel are beginning to be fulfilled. Believers from Samaria, part of the remnant of the northern kingdom, are believing in Jesus and uniting themselves with believers from Jerusalem and Judea. They are being united under one King, one Shepherd.
This is just the beginning. As Isaiah 49:6 says, “It is too small a thing that You should be My Servant to raise up the tribes of Israel and to restore the preserved ones of Israel; I will also make You a light of the nations so that My salvation may reach to the end of the earth” (NASB, see Acts 13:47, Luke 2:32). Acts 1:8 fits so well with Isaiah 49:6. Jesus, the Servant, is raising up a people from Jerusalem, Judea, and Samaria. From that beginning, the good news will go out to the Gentiles (that is, the nations), even to those at the ends of the earth.
Note on sources: It is important to have sources when making points like the ones above. One can find a similar reading of Acts 1:8 and further sources in the excellent work by David Pao, Acts and the Isaianic New Exodus (pp. 94-95, 127-9).