In that day there shall be a fountain opened - Zechariah often repeats, “in that day” Zechariah 12:3-4, Zechariah 12:6, Zechariah 12:8-9, Zechariah 12:11; Zechariah 13:1-2, Zechariah 13:4; Zechariah 14:6, Zechariah 14:8, Zechariah 14:13, Zechariah 14:20, resuming his subject again and again, as a time not proximate, but fixed and known of God, of which he declared somewhat. It is “that day” which “Abraham desired to see, and saw it” John 8:56, whether by direct revelation, or in the typical sacrifice of Isaac, “and was glad:” it was “that day” which “many prophets and kings and righteous men desired to see” Matthew 13:17; Luke 10:24, and in patience waited for it,: “the” one “day of salvation” of the Gospel. He had spoken of repentance, in contemplation of Christ crucified; he now speaks of forgiveness and cleansing, of sanctification and consequent obedience. The “fountain shall be” not simply “opened,” but shall remain open. Isaiah had already prophesied of the refreshment of the Gospel. “When the poor and needy seek water and there is none, and their tongue faileth for thirst, I, the Lord, will hear them, I, the God of Israel, will not forsake them. I will open rivers in high places and fountains in the midst of the valleys” Isaiah 41:17-18; here it is added, “for sin. and for uncleanness.”
There were “divers” Hebrews 9:10 symbolical “washings” under the law; the Levites were “sprinkled with the water of purifying” Numbers 8:7, literally, “the water of taking away of sin: living waters” Numbers 19:17, put to the ashes of an heifer, were appointed as a “water for” (removing) “defilements” (Numbers 19:9, Numbers 19:13, Numbers 19:20-21 bis; Numbers 31:23); “a cleansing of sin” Numbers 19:9. Now, there should be one ever-open fountain for all “the house of David.” Theodoret: “Who that fountain is, the Lord Himself teacheth through Jeremiah, ‘they have forsaken Me, the fountain of living waters’ Jeremiah 2:13; and in the Gospel He says, ‘If any man thirst, let him come unto Me and drink’ John 7:37; and ‘The water which I shall give him, is a fountain of living water, gushing up to everlasting life’ John 4:14. This was ‘open to the house of David;’ for of that kindred He took human nature. It was opened also ‘for the dwellers of Jerusalem,’ for the sprinkling of holy baptism; through which we have received remission of sins.” Cyril: “That, receiving divine and holy baptism, we are sprinkled with the Blood of Christ to the remission of sins, who can doubt?” Dionysius: “Of this fountain much was foretold by Ezekiel, ‘that a fountain should issue forth from the temple of the Lord, and ‘go down into the desert’ Ezekiel 47:1, Ezekiel 47:8-9, and ‘every soul, to whom it shall come, shall live;’ and Joel, ‘A fountain shall come forth of the house of the Lord, and water the valley of Shillim’ Joel 3:18. Of this fountain Peter said to the Jews, when ‘pricked in the heart’ and seeking forgiveness, ‘Let everyone of you be baptized in the Name of Jesus Christ for the remission of sins’” Acts 2:37-38.