In John 4:39-42 we find a progression of belief that is beneficial for our souls. The woman of Samaria returns to town to μαρτυρουσης (testifying). It is a direct result of the woman's testifying that many in the town επίστευσαν (believed). The Greek word πιστεύω (believe) does not always mean saving belief. In John 2:23 we find that many επίστευσαν (believed), but that belief was not a saving belief as verses 24-25 reveal. Likewise, here in 4:39 the belief is not to the level of a saving belief. They believe to the level that they are willing to go outside of the city and test what the woman has spoken. In John 4:42 the crowd specifically says, "It is no longer because of what you said that we believe, for we have heard ourselves, and we know that this is indeed the Savior of the world." They had believed to one degree because of the woman's testimony, but now that have a personalized belief, because they have heard from the Master.
There is a marvelous transition found in these few verses that is necessary for all true believers. We certainly may come to believe as a result of man's testimony, but each person must go to the Word of God and hear from the Lord and come to true saving belief. Perhaps the following illustration may help. I believed in the Grand Canyon when my father told me about it. However, when my eyes looked upon the Canyon I then truly believed. I believed in Jesus when my Sunday School teacher told me about Him, but when my ears heard Him speak from the Word and my eyes saw Him by faith through the Word, I truly believed. Every person needs a personal faith based upon the revelation of Jesus Christ through His Word. It is wonderful to believe upon Him, because He revealed himself in Scripture rather than to believe simply in what someone else has said.
It is good for man to leave the hustle and the bustle of the city and go out of town for the purpose of being alone with Jesus at the well in the middle of the wilderness. Sweet communion can be found when we find a place to meet with Him without the distractions of the world.