On the last day, that great day of the feast, Jesus stood and cried out, saying, “If anyone thirsts, let him come to Me and drink. He who believes in Me, as the Scripture has said, out of his heart will flow rivers of living water.” But this He spoke concerning the Spirit, whom those believing in Him would receive; for the Holy Spirit was not yet given, because Jesus was not yet glorified. (John 7:37–39, NKJV)
Verse 37 begins, “on the last day, that great day of the feast.” Chapter 7 describes a series of interactions Jesus had with the Jewish leaders in Jerusalem. Verse 2 tells us that Jesus was in Jerusalem for the Feast of Tabernacles.
The Old Covenant instructed the Jews to celebrate several festivals throughout the year. The Feast of Tabernacles (Booths, Shelters) was the third of the three major yearly festivals (the first was Passover and Unleavened Bread, the second was Pentecost). It was called the Feast of Tabernacles because on the first day of the feast every household constructed a very simple shelter from tree branches which they lived in for the rest of the eight-day festival.
The first day of the Feast of Tabernacles was a Sabbath day and no secular work was permitted. Every day a series of sacrifices was required including bulls, rams, lambs, and goats, as well as grain and drink offerings. Also, by New Testament times, a tradition developed where each of the seven days of the Feast a priest led a parade of people making joyful music to the Pool of Siloam, where he drew water using a golden pitcher and brought it back to the temple.
On the eighth day, a Sabbath day, each household took down its shelter and there was a great community feast, but the priest didn’t go down to the Pool of Siloam. This is the day and the great feast when Jesus stood up and said, “He who believes in Me, … out of his heart will flow rivers of living water” (John 7:38).
So on the eighth day, the priest stopped going to get water at the Pool of Siloam. And on the eighth day, Jesus stood up and claimed to offer Living Water. John tells us plainly in verse 39 that Jesus was talking about the Holy Spirit. So here, Jesus used the symbolism of the Jewish Feast of Tabernacles and the water from the Pool of Siloam to share the promise of the Holy Spirit for all who believe with everyone at the Feast.
But the timing of Jesus’ statement about himself being the source of Living Water—the Holy Spirit—has additional significance. The Feast of Tabernacles was instructed as a festival of remembrance for the time the Israelites spent wandering in the wilderness.
It might seem like the shelters were a form of fasting—depriving them of the comforts of living in their own homes. And in a literal sense they were, but spiritually, something else was going on. The shelters were a physical reminder of how God delivered the Hebrew people from bondage in the house of Egypt and into freedom that comes through trusting God for everything they need.
In Exodus 16, the Israelites complain to Moses about not having food and the LORD provided Bread from Heaven for their daily sustenance. In Exodus 17, the Israelites complain to Moses about not having any water and we see how the LORD provides water for Israel. Water that flows from the rock, the rock which was stricken, in the wilderness, so that the Israelites might live. That rock is a picture of Jesus Christ, and the water is a picture of the Holy Spirit.
When Jesus spoke with the Samaritan woman at the well of Jacob in John 4, he said to her, “If you knew the gift of God, and who it is who says to you, ‘Give Me a drink,’ you would have asked Him, and He would have given you living water” (John 4:10).
On the last day of the Feast of Tabernacles—the Jewish festival that celebrates God’s provision for the Israelites in the wilderness—Jesus stood up, quoted Isaiah 55:1, and proclaimed, “If anyone thirsts, let Him come to me and drink. He who believes in me, … out of his heart will flow rivers of living water.”
Christ is the Rock of our salvation. And for all who are willing to come to him and ask, He gives us eternal life. But God didn’t intend for our eternal inheritance to be characterized by a dry, arid wasteland of legalistic intellectualism. Nor did He intend it to be a wild-eyed, unrestrained exhibition of unbridled emotionalism. God intends for his gift of eternal life to be characterized by the outpouring and overflowing of His life-giving Spirit, Who nourishes us daily, fill us with God’s love, grace and mercy, leads us in all truth, empowers us to serve His Kingdom, and comforts and strengthens us even in our darkest times of grief, frustration, and heartache.
But such a vibrant life in the Spirit has one recurring condition. We can’t do it on our own power and He won’t force it on us. To experience the life-transforming power of the Spirit in our lives, day-by-day and moment-by-moment, we have to humble ourselves and draw near to our Lord Jesus Christ. As the Scriptures say, we must go to Him to drink.
 R. K. Harrison, “Booths, Feast of,” in The International Standard Bible Encyclopedia, Rev. ed., ed. Geoffrey W. Bromiley (Wm. B. Eerdmans, 1979–1988), 535. Logos Bible Software.
 Merrill F. Unger, “Festivals,” in The New Unger’s Bible Dictionary, ed. R.K. Harrison (Chicago: Moody Press, 1988). Logos Bible Software.