The quotation of Yah'shua (Jesus), "Out of his heart shall flow rivers of living water", is not an exact quotation from the Old Testament but may be a modification of Zechariah 14:18 which reads, "On that day living waters shall flow out of Jerusalem". The context of Yah'shua's (Jesus') quote is the last day of the Feast of Tabernacles (Sukkot) at Jerusalem in the temple. John then explains that Yah'shua's (Jesus') reference was to the Ruach (Spirit) which was to be received by the believers once Yah'shua (Jesus) had been glorified (7:39). This is no doubt a prophecy about the Day of Pentecost (Shavu'ot).

Why the association between the Ruach haQodesh (Holy Spirit) and water? Throughout the Old Testament, water is used both in terms of a life-giver and as a purifier. Prosperity and fruitfulness is compared to being "well-watered" (Is.58:11) which Yahweh will always provide the righteous with (Is.49:10). "He (the righteous man) is like a tree planted by streams of water, that yields its fruit in its season, and its leaf does not wither. In all he does, he prospers" (Ps.1:3). The abundance of water in Israel is a sign of the "last days" or eschatology (Is.44:3) and specifically the prophets declared that water would come out of the Temple at Jerusalem to the east and to the west (Joel 3:18; Zec.14:8). But this is more than ordinary water, for "on that day shall there be a fountain opened for the house of David and the inhabitants of Jerusalem to cleanse them from sin and uncleanliness" (Zec.13:1) and the command is, "Ho, everyone who thirsts, come to the waters ..." (Is.55:1). Thus the presence of actual physical water emerging from Jerusalem is to be the sign in the last days that an abundance of "spiritual water" will be available to cleanse sinful Israel. The illustration is made clear in Joel 2:28f where Yahweh says that "... it shall come to pass that I will pour out My Ruach (Spirit) on all flesh ..." which will cause men and women, young and old, to prophesy and have inspired dreams. The reference to "pouring" out the Ruach (Spirit) makes a vivid connection between "spirit" and "water". The writer of Ecclesiasticus (Sirach, Apocrypha) writes: "...they that drink me shall yet be thirsty..." (Ecclus.24:21).

If Yah'shua (Jesus) was referring to Zechariah 14:8 when He quoted scripture, what was the connection between "Jerusalem" and "heart"? Jerusalem was, in a sense, the heart of Israel. It was also the place where Yah'shua (Jesus) was crucified and atoned for Israel and the world. Water gushed out of Yah'shua's (Jesus') body when He was speared by the soldier. Any or all of these concepts may connect with Yah'shua's (Jesus') meaning. Belief in Yah'shua (Jesus) assures the believer that the Ruach haQodesh (Holy Spirit) will dwell in his heart, purifying him like a "river of living water". Had Israel repented and believed in Him, the Ruach (Spirit) would have come out of the heart of Israel -- out of Jerusalem - like "living water". But Israel did not. Instead, at that time, a "remnant" of believers came out of Jerusalem (2 Ki.19:31; Is.37:32). Thus many of the prophecies of the Old Testament quoted above must relate to a future time -- the Second Advent of Yah'shua (Jesus) -- for as yet neither has Israel as a whole accepted Christ not have rivers of water come under the Temple area of modern Jerusalem, nor is there indeed any Temple there yet. Finally, we should not forget that water is associated with baptism; the believers, at the time Yah'shua (Jesus) had spoken, had likely been baptised by John the Baptist or one of the Apostles. They had been baptised with water but had yet to understand the baptism of the Ruach (Spirit) or of fire. Almost certainly the living water flowing out of the heart of the believers referred in some way to the baptism of the Ruach (Spirit) at Pentecost (Shavu'ot).