Zechariah 13:1 promises a "fountain opened... for sin and for uncleanness." Under the Old Covenant, cleansing was a ritual process involving the bronze laver and repetitive sacrifices. It was a restricted, temporary solution. The "opened" nature of this fountain suggests a permanent accessibility that the Law could never provide.
John’s Gospel provides the visual fulfillment of this fountain. When the soldier pierced Jesus’ side, "immediately blood and water came out" (John 19:34). This was not merely a medical observation, but a theological sign. The blood provides atonement for sin; the water provides cleansing from uncleanness. In the New Creation, the fountain remains open to all, providing a "once for all" purification of the conscience.