What does John 4:40 mean?

One can only imagine how rattled the disciples must have been at this turn of events. Samaritans were ethnic and religious half-breeds. As a result, most Jews despised them and refused to have any unnecessary contact with them (John 4:9). And yet, in this episode, Jesus has spoken at length to someone who is not only Samaritan, but a woman (John 4:27). That same woman has brought many of the townspeople to meet Jesus (John 4:30), when none of the disciples did. And, now Jesus is not only interacting with these people, He is staying for several days!

This, in part, is Jesus putting into practice what He would command of the apostles after His ascension. In Acts 1:8, after rising from the dead, and just before ascending in Heaven, Jesus instructs His followers. He tells them to "be [His] witnesses in Jerusalem and in all Judea and Samaria, and to the end of the earth." So far in the gospel of John, Jesus has traveled from Jerusalem, to Judea, and into Samaria. Here, He will be recognized as "the Savior of the world" (John 4:42).