"37 On the last day of the feast, the great day, Jesus stood up and cried out, “If anyone thirsts, let him come to me and drink. 38 Whoever believes in me, as the Scripture has said, ‘Out of his heart will flow rivers of living water.’”39 Now this he said about the Spirit, whom those who believed in him were to receive, for as yet the Spirit had not been given, because Jesus was not yet glorified.
40 When they heard these words, some of the people said, “This really is the Prophet.” 41 Others said, “This is the Christ.” But some said, “Is the Christ to come from Galilee? 42 Has not the Scripture said that the Christ comes from the offspring of David, and comes from Bethlehem, the village where David was?” 43 So there was a division among the people over him. 44 Some of them wanted to arrest him, but no one laid hands on him."
John 7:37-44
At the climax of the feast, Jesus stood up and uttered the wonderful words recorded in 37, 38. Taken even by themselves, they are rich in the message they bear, but they become infinitely more so when their context is understood, and it is this we must study with great care. The reference to living water links up with the water used in the festival ceremonial (see Note for Friday, 14th), and its symbolising of the water from the rock during Israel's wilderness journeyings. It is as if Jesus were saying, 'You are remembering how thirst was quenched in the wilderness by water from the smitten rock. I am that Rock, and faith in Me will bring supplies of living water that will quench your thirst for ever more. Come to Me and drink. What happened in olden time was but an illustration, a symbol, of what was to happen when Messiah came. I am He, and living water has now come'. In the words He spoke here, therefore, He claimed to be the fulfilment of Old Testament promise and prophecy. But more. He yearned that in their observance of the feast they should see its fulfilment in Himself. He could see that although they were celebrating it, they were really strangers to its real message. They were 'outside' it - it was, to them, something that happened long ago, and they were looking back at it as such. It had nothing to say to their present need. This was the real tragedy about Judaism then. It was not a living religion; it had a great and wonderful tradition, but it was only a shell. There was no kernel in it. It was a formal, lifeless, second-hand religion. All along, Jesus perceived this tragedy and offered Himself to men as One who could make real the message of the Scriptures and fulfil all its promises to them. All this is involved in a true understanding of Jesus' words here.