Once again, as we look at the next two verses we see yet again just how awesome and amazing Jesus is at revealing truth in His encounters with the lost. Jesus doesn't respond to Her question, "Are You greater than our father Jacob, who gave us the well, and drank from it himself, as well as his sons and his livestock?" in a way that you or I might. He doesn't start making claims about His greatness or listing off His credentials or even offering up His title. Instead He responds to her question of "Are You greater? Is what You have to offer of more value?" by saying "Whoever drinks of this water will thirst again, but whoever drinks of the water that I shall give him will never thirst. But the water that I shall give him will become in him a fountain of water springing up into everlasting life."
He immediately does the thing she asks Him to do. He reveals to her that what He has is in fact is of greater value! He compares what He has to offer with what she already has and knows. He points to the well and reminds her that while this water could quench her physical thirst its effects last just so long and she would indeed thirst again. He reminds her that she will be burdened daily with the labor of always needing to draw more. As she is contemplating this truth, this daily reality that she is all too familiar with He then compares it with the 'living water' that He is offering her and thus revealing its worth, its greater value when He says, "but whoever drinks of the water that I shall give him will never thirst. But the water that I shall give him will become in him a fountain of water springing up into everlasting life."
He declared His greater value by letting her know that His offer of the gift of living water was of a different kind, a different quality! He tells her that it would quench her thirst beyond the natural thirst that her well water could. He declared to her that it would be 'a fountain of water springing up into everlasting life.' The 'living water' that He was offering her would be by its very nature forever and always undiminished. It would be a fountain springing up, continually bubbling up within her soul to nourish and to satisfy its desires. He showed her that its value went beyond the physical, the natural, but to the spiritual and to everlasting life.
With this answer, this comparison, He accomplished the very thing He intended when she first encountered Him at the well and He asked, "Give Me a drink." She is now in the the place where she is truly thirsty! Because of the words that He spoke and the truth they revealed to her He has stirred up a longing in her soul. She now longs with a desire for more than she has know in the past. She came for water but now, she has a different thirst and it is now a thirst for the living water that He offers!