“And I will sprinkle clean water on you and you will be clean. From all your filthiness and from all your idols I will cleanse you. I will also give you a new heart, and I will put a new spirit within you. And I will take away the stony heart out of your flesh, and I will give you a heart of flesh.”
Let us first consider what was here on offer. ‘Clean water' is mentioned nowhere else in the Bible. The ancients did not think in terms of clean water and dirty water. The only clean water could be caught in the falling mountain springs, and was comparatively rare, and they mostly bathed and drank with what we would call dirty water, but which they saw as relatively clean. Thus this description must be seen as having a special significance, and that significance was that it was ‘cleansed water', water that had been (at least theoretically) made clean through sacrifice, sprinkled with blood or with the ashes of a heiffer.
In Leviticus the cleansing of a defiled house required sprinkling with a mixture of blood and ‘living' water, the bird having been slain over the water (Leviticus 14:51), and in Numbers 8:7; Numbers 19:2-22 the ‘water of separation' (Numbers 19:9; Numbers 19:20 - this was also called ‘living water' - Numbers 9:17) is mentioned. It was water that had been sprinkled with the ashes of a red heiffer (Numbers 19:2), and was kept aside for the purifying by sprinkling of those who had touched a dead body. Thus in both cases the water had been cleansed by sacrifice and the shedding of blood.
So when the priestly Ezekiel spoke of ‘clean water' he had in mind water that had been cleansed by sacrifice. And indeed this was the only kind of water that was ever sprinkled. Thus the cleansing was to be through the blood of sacrifice, applied through the sprinkled water. This was probably also what the Psalmist had in mind in Psalms 51:7 (note the parallel phrase).
But this water was here to be sprinkled by God Himself acting as the high priest. Before anything else the people need to be cleansed, by the divine water of separation sprinkled on them by God, from their defilement brought on them by their sinful ways and their idolatry. There is no cleansing without the shedding of blood. This pointed forward to the fountain opened for sin and uncleanness (Zechariah 13:1), and its efficacy depended on the One Who would be slain as a sacrifice for the sins of the whole world, Whose benefit reached backwards to ‘sins done aforetime' (Romans 3:25).
It should be recognised and acknowledged that to the priest Ezekiel there could be no entry back into the promised land, now cleansed from defilement by time, without such a cleansing. Otherwise what purpose in the exile?
(We should note that washing with ordinary water never cleansed. It was only preparatory, and was regularly followed by the phrase ‘and will not be clean until the evening'. It only represented the washing away of ‘earthiness' preparatory to cleansing (see Ezekiel 44:18). It did not itself cleanse).
Then they were to receive a new heart and a new spirit, indeed God's Spirit (Ezekiel 36:27). The heart included the mind, the will and the emotions, it was the whole of the inner man. The spirit was the life principle within, the inner impulse, and while it could include the activities of heart, mind and will, it was also that which was Godward (Ecclesiastes 3:21; Ecclesiastes 12:7), and was affected by God's Spirit. So the idea here is of the renewing of the whole inner man, and of awakening towards God.
Its effect is then described. ‘And I will take away the stony heart out of your flesh, and I will give you a heart of flesh.' Instead of hardness there would be tenderness, instead of obduracy there would be yielding, instead of coldness there would be warmness, instead of disobedience there would be obedience. The law would be put in their inward parts and in their hearts, and they would ‘know Yahweh' individually through the new covenant (compare Jeremiah 31:33-34).
These wonderful words must not be restricted to any particular moment in time, important though Pentecost was. This is the nature of Biblical prophecy. We need not doubt that it began on the first returning exiles, and it continued in the time of Haggai and Zechariah, when God worked through His Spirit in the life of Zerubbabel (Zechariah 4:6). It was continually on offer to His people (Ezekiel 18:31). But it certainly had a full expression at and after Pentecost (2 Corinthians 5:17), and through the ministry of Jesus (John 3:1-6; John 4:10-14; John 4:24; John 6:63; John 7:37-38; John 20:22), and continues today and will continue to the end. What began to be fulfilled at the return from exile has continued through the ages. The cleansing is constantly needed.