What does John 10:42 mean?

Jesus has temporarily left the area immediately around Jerusalem, due to rising threats from the local religious leaders (John 10:39–40). He has gone to Perea, a region were John the Baptist preached prior to Jesus' public ministry (John 1:19–29). That preaching, it seems, has made the people much more receptive to Jesus' teachings. Those who have heard John's message recognize Jesus on the basis of His miracles, and the fact that He fits the predictions given them by John (John 10:41). This is similar to the way in which the testimony of the Samaritan woman opened up interest in the town of Sychar (John 4:39), which also prepared that area for the apostles after Jesus' ascension (Acts 8:4–8).

Jesus' avoidance of danger is only temporary. Soon after this, He will return to Judea, much to the fear of his disciples (John 11:6–8). He will then re-enter Jerusalem for the last time before being arrested and executed on the cross.