Philip went through the Scriptures in Isaiah explaining how Jesus was the one that was being talked about and I am sure he gave the Eunuch a complete interpretation on how Jesus fulfilled these prophesies. There is no question that what Philip taught him was what made him BELIEVE and the BELIEVE was connected to the interpretation of Jesus sacrificial offering written about in Isaiah that Philip told him about. How could you miss that? What do you think the Eunuch believed? How long did Philip teach him out of the book of Isaiah explaining how Jesus fulfilled these prophesies exactly. How could anyone possibly interpret Isaiah and apply it to Jesus without talking about the cross and resurrection? What do you think Philip told the Eunuch about Jesus that made the Eunuch believe. What do you think the Enuuch believed? That there was once a man named Jesus once upon a time in Mexico?
Its the same as in John 20:31.
Its the same when Peter replied to Jesus in Matt 16:16 16 And Simon Peter answered and said, Thou art the Christ, the Son of the living God.
Its the same when Martha told Jesus in John 11:27 She saith unto him, Yea, Lord: I believe that thou art the Christ, the Son of God, which should come into the world.
Do you realized the consistency in all these scripture accounts? To be saved under the gospel of the kingdom is based on believing in Jesus's identity, and not what Jesus did on the cross. After that, then water baptism needed to be done as part of the salvation process.
But that is not the gospel that saves today, as I have stated in my original post. The gospel that saves today requires you to believe what Jesus did at the cross, and its all about that