What does John 3:24 mean?

The gospel of John explains many Hebrew ideas to readers (John 1:38, 40–42). But it was written long after the rest of the Gospels, so John assumes readers are familiar with the writings of Matthew, Mark, and Luke. Matthew chapter 14, Mark chapter 6, and Luke chapter 3 explain how the Baptist was arrested and eventually executed (Mark 6:17–18, 27).

Before the Baptist was taken, the region around Jerusalem would have heard from both Jesus and John the Baptist (Matthew 3:1–6). This must have had quite an impact (John 3:23). Here, the Baptist chose a location with "plenty of water," presumably because there were that many people who wanted to be baptized. Rather than taking their message to the hard-hearted city, they preached in the countryside.

This was a time for Jesus to teach His disciples (John 3:22). This is a crucial part of the Christian life: spending time with God. The time these men spent with Jesus prior to His crucifixion is what prepared them for life as apostles.