The gospel moved from Jerusalem and a gospel-shaped message for Jews to the Samaritans. When it did, this is what we read in Acts 8:

4 Those who had been scattered preached the word wherever they went. 5 Philip went down to a city in Samaria and proclaimed the Christ there. 6 When the crowds heard Philip and saw the miraculous signs he did, they all paid close attention to what he said. 7 With shrieks, evil spirits came out of many, and many paralytics and cripples were healed. 8 So there was great joy in that city.
9 Now for some time a man named Simon had practiced sorcery in the city and amazed all the people of Samaria. He boasted that he was someone great, 10 and all the people, both high and low, gave him their attention and exclaimed, ?This man is the divine power known as the Great Power.? 11 They followed him because he had amazed them for a long time with his magic. 12 But when they believed Philip as he preached the good news of the kingdom of God and the name of Jesus Christ, they were baptized, both men and women. 13 Simon himself believed and was baptized. And he followed Philip everywhere, astonished by the great signs and miracles he saw.

14 When the apostles in Jerusalem heard that Samaria had accepted the word of God, they sent Peter and John to them. 15 When they arrived, they prayed for them that they might receive the Holy Spirit, 16 because the Holy Spirit had not yet come upon any of them; they had simply been baptized into the name of the Lord Jesus. 17 Then Peter and John placed their hands on them, and they received the Holy Spirit. 18 When Simon … 25 When they had testified and proclaimed the word of the Lord, Peter and John returned to Jerusalem, preaching the gospel in many Samaritan villages.

What do we learn?
1. Gospel preaching is “word” preaching (and not just missional lifestyle) (v. 4). This word must at least be connected to the preaching of Stephen in Acts 7 — and his preaching is a narrative unfolding of Israel’s history when it becomes shaped as the Story that finds completion in Jesus as Messiah.
2. The “word” is also about Christ (v. 5) and it is attended by supernatural power.
3. The “word” of the gospel preaching is also about the “kingdom of God” and “the name of Jesus Christ” (v. 12) — it leads to baptism for both men and women (a sign of incorporation and gender reconciliation).
4. We can assume the gospel Peter and John preached is the gospel in Acts 8:12 — the story of Israel come to completion in Jesus as Messiah and attended to by the Holy Spirit. So, we are not surprised to see “word of God” and “Holy Spirit” when we hear they are preaching.
Notice how rarely, though not entirely, the “benefits” of this gospel are mentioned. Instead of saying “for salvation” they say “Christ” and “kingdom.”