37 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.
38 He who believes in Me, as the Scripture has said, out of his heart will flow rivers of living water.”
39 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.
feast (v.37) — Tabernacles — “Behold, I will stand before you there on the rock in Horeb; and you shall strike the rock, and water will come out of it, that the people may drink.” And Moses did so in the sight of the elders of Israel (Exodus 17:6).
last day (v.37) — The Feast of Tabernacles terminated with the eighth day. It was on this last day, that the voice of our Lord was heard uttering this most blessed invitation and promise. For seven days water had been drawn from the brook Siloam and poured out, under the rejoicing of the people assembled to keep the feast. It was a memorial of the miracle in their history, when the Lord, during their wilderness experience, supplied water out of the cleft of the rock. But more than that, for the well informed Israelite, who believed the promises of God made to the nation, it was prophetic. Zechariah’s final vision tells of the time “when living waters shall go out from Jerusalem” (Zechariah 14:8). Ezekiel, too, had beheld the waters like a mighty river flowing forth from the great temple. And in the distant past Balaam, likewise, had spoken a similar prophecy (Numbers 24:7). All these prophecies will be fulfilled in the day the King comes back to be in the midst of His people. The last great day of the feast was called “the Hosanna Rabba,” when the air was fairly rent with the Hosannas of the multitudes. But on the eighth day the ceremony of pouring out water ceased. It was symbolical of the fact that after the wilderness wanderings were over they entered the promised land, where the springs of water supplied all their need to the full. —Gaebelein, page 149.
The national promise was impossible at this time — Jesus would be rejected. But He promises a new giving of water, the Holy Spirit.
rivers of living water (v.38) — The believer, indwelled by the Spirit, is the means of blessings to other believers and to the world. Once a vessel is filled with water, it overflows. The quote is from:
Psalm 78:16 — He also brought streams out of the rock, and caused waters to run down like rivers.
Isaiah 41:17-18 — The poor and needy seek water, but there is none, their tongues fail for thirst. I, the LORD, will hear them; I, the God of Israel, will not forsake them. I will open rivers in desolate heights, and fountains in the midst of the valleys; I will make the wilderness a pool of water, and the dry land springs of water.
Isaiah 44:3 — For I will pour water on him who is thirsty, and floods on the dry ground; I will pour My Spirit on your descendants, and My blessing on your offspring.
Isaiah 58:11 — The LORD will guide you continually, and satisfy your soul in drought, and strengthen your bones; you shall be like a watered garden, and like a spring of water, whose waters do not fail.
Zechariah 14:8 — And in that day it shall be that living waters shall flow from Jerusalem, half of them toward the eastern sea and half of them toward the western sea; in both summer and winter it shall occur.