What does John 4:2 mean?

The sudden increase in Jesus' ministry would have attracted attention from the Pharisees. John the Baptist was baptizing so many people that having enough room in the water was a concern (John 3:23). His popularity was enough to attract an investigation (John 1:19), and eventually created a controversy (John 3:25). Jesus is already surpassing that level of success.

However, a major theme of the gospel of John is God's timing. Jesus is committed to obeying the will of the Father, including both "when" as well as "what." The moment to begin confronting local religious leaders will come soon (John 5:18–19), but not yet. So, as this is not the right time, Jesus moves along to Galilee. Rather than taking the typical Jewish route around Samaria, though, the will of the Father obligates Jesus to go through the region (John 4:4).

This verse also clearly indicates that Jesus did not perform baptisms personally. In the early church, unfortunately, who baptized whom quickly became a point of argument (1 Corinthians 1:12–15). If being baptized by Paul gave people an excuse to boast, imagine the potential problems if someone could claim to have been baptized by Christ Himself! Most likely, this is the reason Jesus left baptism to His disciples. These passages also underscore the idea that baptism is not a requirement for salvation (1 Corinthians 1:17).