Acts 8: εὐηγγελίσατο - preached

In Acts 7 and before, there was a community in Jerusalem who was sharing the bread; but this community faced a great persecution. Most Christians fleed from Jerusalem to other places after the death of Stephen, but wherever they went they spread the gospel. In particular, Philip preached to the eunuc who was reading Isaiah 53. 

35 Then Philip opened his mouth, and beginning from this Scripture he preached/εὐηγγελίσατο/euēngelisato Jesus to him.

When we read the gospel of Luke (for instance), it seems that the gospel/evangelium is about the coming of the kingdom of God, but in Acts, it becomes clearer that the Messiah is the Way to connect to the Lord. It was clear to the first Christians that they should evangelize, spread the gospel, spread who is Jesus.

Perhaps I have to adjust what the gospel is. In my mind, the gospel is all about being accepted by the Lord through Jesus, so I can rest in Him and perhaps rest of preaching. But there was some necessity of the first Christians to preach. Why? Perhaps because they discovered a great treasure, they were really glad and they had to spread the good news as in:

39 When they came up out of the water, the Spirit of the Lord snatched Philip away; and the eunuch no longer saw him, but went on his way rejoicing.