The following is the good news Israel was waiting for and had been promised throughout the OT.
Luke 1
67 And his father Zacharias was filled with the Holy Ghost, and prophesied, saying,
68 Blessed be the Lord God of Israel; for he hath visited and redeemed his people, (what kind of redemption?)
69 And hath raised up an horn of salvation for us in the house of his servant David; (what kind of salvation?)
70 As he spake by the mouth of his holy prophets, which have been since the world began:
71 That we should be saved from our enemies, and from the hand of all that hate us; Ah, a physical salvation from their enemies
72 To perform the mercy promised to our fathers, and to remember his holy covenant;
73 The oath which he sware to our father Abraham,
74 That he would grant unto us, that we being delivered out of the hand of our enemies might serve him without fear,
75 In holiness and righteousness before him, all the days of our life.
This is all about the nation of Israel being delivered from their enemies and given a physical kingdom so they can serve God without fear. That’s the gospel of the kingdom that was preached prior to the resurrection. The disciples were still asking about it after the cross.
Acts 1:6 When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel?