What does Acts 8:36 mean?

By the leading of an angelic message, Philip has come upon an Ethiopian court official who is reading from Isaiah 53:7–8 which prophesies the abuse and death of the Suffering Servant (Acts 8:26–33). Philip explains how the passage talks about Jesus of Nazareth, how the prophecy was fulfilled, and how Jesus now offers salvation (Acts 8:35). The Ethiopian quickly accepts Philip's explanation as well as the forgiveness of Jesus.

The area where they are is described as a "desert place" (Acts 8:26). That doesn't mean it's nothing but sand and rock, it just means it's uninhabited. Even grassland and wilderness in Israel can have pools or streams of running water. It's reasonable to think that if the Holy Spirit could show Philip how to get to the Ethiopian, He could do so near water enough to be baptized.

In the early church, new converts were baptized immediately (Acts 2:41; 8:12; 9:18; 10:47–48; 16:15, 33; 19:5). Baptism was a sign that a person accepted the message of a teacher and wanted to publicly identify with that message. Today, churches tend to have a person go through a class to make sure they understand Christianity and what baptism represents. That didn't happen in the early church, and sometimes unbelievers got caught up in the enthusiasm and were baptized without being saved—which seemed to be the case with Simon the magician (Acts 8:13).

It's important to understand the biblical meaning of baptism. It means someone is voluntarily identifying themselves with the universal church established by Jesus' crucifixion and resurrection and the coming of the Holy Spirit. Today, a church may require such a step of obedience as a condition for membership in that congregation. However, baptism doesn't primarily mean a person is joining some sect or denomination. In the same way, it neither proves a person is saved, nor is it required for salvation.