New Defender's Study Bible Notes
13:1 a fountain opened. There will be living waters emerging from Jerusalem in that day (Zechariah 14:8), but the fountain mentioned in this verse is “for sin and uncleanness.” It can only refer to the cleansing blood of the Savior (Ephesians 1:7; Revelation 1:5; etc.), which is, for the first time, applied here to the whole nation of Israel. Possibly their national repentance will be couched in the words of Isaiah 52:13–53:12.